CN113248355B - Preparation method of p-chlorobenzaldehyde - Google Patents
Preparation method of p-chlorobenzaldehyde Download PDFInfo
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- CN113248355B CN113248355B CN202110764507.4A CN202110764507A CN113248355B CN 113248355 B CN113248355 B CN 113248355B CN 202110764507 A CN202110764507 A CN 202110764507A CN 113248355 B CN113248355 B CN 113248355B
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
- C07C45/44—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by reduction and hydrolysis of nitriles
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C253/00—Preparation of carboxylic acid nitriles
- C07C253/24—Preparation of carboxylic acid nitriles by ammoxidation of hydrocarbons or substituted hydrocarbons
- C07C253/28—Preparation of carboxylic acid nitriles by ammoxidation of hydrocarbons or substituted hydrocarbons containing six-membered aromatic rings, e.g. styrene
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Abstract
The invention providesA process for preparing p-chlorobenzaldehyde includes such steps as filling the ammoxidation catalyst V in fixed-bed reactor2O5Heating, introducing nitrogen and hydrogen to make ammoxidation catalyst V2O5Activating, ammoxidation catalyst V2O5After activation, continuously introducing nitrogen for purging, introducing mixed gas of ammonia gas and oxygen gas, and ammonia gas and p-chlorotoluene in advance, after the gas velocity is stable, introducing p-chlorotoluene by using a feed pump, carrying out ammoxidation reaction to generate p-chlorobenzonitrile, adding the p-chlorobenzonitrile into a high-pressure reaction kettle, adding reduction catalysts Raney nickel and formic acid solution, replacing air in the kettle with nitrogen, introducing hydrogen gas, heating, reacting, keeping the temperature and pressure, cooling and filtering to obtain filtrate, extracting the filtrate with toluene, and recovering the toluene under reduced pressure to obtain the p-chlorobenzaldehyde. The method has simple process operation, avoids using chlorine gas, and does not generate a large amount of hydrogen chloride tail gas, waste water, waste acid and the like. Low requirement on equipment, small comprehensive investment, quick response and high conversion rate, and belongs to the technical field of organic chemical industry.
Description
Technical Field
The invention belongs to the technical field of organic chemical industry, and relates to a preparation method of p-chlorobenzaldehyde.
Background
P-chlorobenzaldehyde is an important novel intermediate for pesticides, medicines and dyes. In the aspect of medicine, p-chlorobenzaldehyde is condensed and cyclized with mercaptopropionic acid to prepare the Finaflu. In the aspect of pesticides, p-chlorobenzaldehyde is used for synthesizing herbicides, such as Maidi powder, plant growth regulators, paclobutrazol and uniconazole and the like. In the aspect of dyes, p-chlorobenzaldehyde is used for synthesizing acid blue 7BF, acid brilliant blue 6B and the like.
At present, the preparation method of p-chlorobenzaldehyde generally adopts the following modes:
patent CN104557492A describes that p-chlorobenzol is irradiated by a mercury lamp to react with chlorine in the presence of an initiator, the chlorination temperature is 90-140 ℃, a mixture of p-chlorobenzyl chloride and p-chlorodichlorine is obtained, the average chlorination degree is controlled to be 1.4-1.6, and the catalytic hydrolysis is carried out in 3-6wt% nitric acid solution for 6-12h, so as to obtain the p-chlorobenzaldehyde. However, the method has the advantages of long reaction time, difficult control of chlorination depth and generation of various mixtures, and chlorine can replace methyl and can directly chlorinate benzene rings, so that the product purity is not high, the selectivity is poor and is only about 80%, the conversion rate is low, byproducts are more, and the post-treatment difficulty is high. Meanwhile, a large amount of hydrogen chloride tail gas is generated in the chlorination process, the generated hydrogen chloride is not high in purity and narrow in utilization range, and can only be absorbed by alkali to generate a large amount of waste salt. The hydrolysis process uses metal salt catalyst, which produces a large amount of waste water, and the metal salt catalyst is difficult to recycle, has high cost and causes great environmental pollution.
In patent CN104447251A, p-chlorotoluene illumination is still used for reacting with chlorine, but an initiator phosphorus dichloride is used and only ordinary illumination is used, so that an ultraviolet lamp is abandoned, energy consumption is greatly saved, and selectivity is improved. However, the process still has the defects that a large amount of hydrogen chloride tail gas is generated in the chlorination process of the chlorination process, a large amount of waste water and waste acid are generated by hydrolysis, the environmental pollution is serious, the subsequent treatment difficulty is high, and the equipment requirement is high. At present, the yield of the product is only about 88 percent, and the market competitiveness is relatively small. The hydrolysis process also uses metal salt catalyst, which produces a large amount of waste water, and the metal salt catalyst is difficult to recycle, so the cost is high and the environmental pollution is large.
The preparation method is not suitable for large-scale application and production, has the problems of complex operation, high cost, poor safety and sanitation conditions and the like, influences the economic benefit and needs to be further improved.
Disclosure of Invention
In order to solve the technical problems, the technical scheme adopted by the application is to provide a preparation method of p-chlorobenzaldehyde, which comprises the following steps:
step (1): and (3) oxidation reaction: filling an ammonia oxidation catalyst V into a fixed bed reactor2O5Heating, introducing nitrogen and hydrogen to make ammoxidation catalyst V2O5Activating, ammoxidation catalyst V2O5After activation, continuously introducing nitrogen for purging, introducing mixed gas of ammonia gas and oxygen gas and ammonia gas and p-chlorotoluene in advance, after the gas velocity is stable, introducing p-chlorotoluene by using a feed pump, and carrying out ammoxidation reaction to generate p-chlorobenzonitrile;
step (2): and (3) hydrolysis reaction: adding p-chlorobenzonitrile into a high-pressure reaction kettle, adding reduction catalysts Raney nickel and formic acid solution, replacing air in the kettle with nitrogen, filling hydrogen, heating, reacting, keeping the temperature and pressure, cooling and filtering to obtain filtrate, extracting the filtrate with toluene, and recovering the toluene under reduced pressure to obtain p-chlorobenzaldehyde.
Preferably, the temperature of the oxidation reaction is 330-380 ℃.
Preferably, the molar ratio of ammonia to oxygen is 1: 1.6-1.8.
Preferably, the molar ratio of the p-chlorotoluene to the ammonia gas is 1: 1.1-1.3.
Preferably, the space velocity of the p-chlorotoluene is 1.1-1.3h-1。
Preferably, the temperature of the hydrolysis reaction is 60-80 ℃.
The invention provides a preparation method of p-chlorobenzaldehyde, which takes p-chlorotoluene as a raw material, introduces ammonia gas with a certain proportion into the raw material at a certain temperature in the presence of an ammoxidation catalyst to react with air, performs ammoxidation to generate p-chlorobenzonitrile, and adds the catalyst into the p-chlorobenzonitrile under the condition of acid or acid salt water solution to perform hydrogenation reduction hydrolysis reaction to generate the p-chlorobenzaldehyde. The method has simple process operation, avoids using chlorine gas, and does not generate a large amount of hydrogen chloride tail gas, waste water, waste acid and the like. Low requirement on equipment, small comprehensive investment, quick return, high conversion rate, good selectivity, simple post-treatment, environmental protection, low cost and great market competitiveness.
Detailed Description
Example 1
(1) And (3) oxidation reaction: taking a fixed bed reactor, and filling an ammoxidation catalyst V2O5After the volume is 25ml, the temperature is raised to 350 ℃, nitrogen is used for purging for 1h at the gas speed of 200sccm,introducing hydrogen gas to purge for 1h at a flow rate of 100sccm, introducing ammonia gas to purge for 0.5h at a flow rate of 50sccm to activate the ammoxidation catalyst V2O5After the temperature is stable, introducing a mixed gas of ammonia gas and oxygen gas with the molar ratio of 1:1.6 and ammonia gas and p-chlorotoluene with the molar ratio of 1:1.2 into the fixed bed reactor for 10min, taking 20g of p-chlorotoluene, and using a feed pump to make the space velocity of 1.2h-1P-chlorotoluene 0.5g/min is introduced into the reactor, p-chlorobenzonitrile is collected at the lower end, 21.77g of crude p-chlorobenzonitrile is obtained, and the content of the p-chlorobenzonitrile is measured to be 96%. The reaction equation is as follows:
(2) and (3) hydrolysis reaction: adding a crude product of p-chlorobenzonitrile obtained by oxidation reaction into a high-pressure reaction kettle, adding 1.1g of Raney nickel reduction catalyst and 80g of 80% formic acid solution, wherein the adding amount of the catalyst is 5% of the mass of the fed material, charging 5MPa hydrogen, heating to 75 ℃, keeping the temperature and the pressure for 1h, paying attention to the change of the hydrogen pressure in the heat preservation process, and ensuring that the hydrogen pressure is not lower than 3MPa in the reaction process until the pressure is not reduced; after the reaction is finished, the reaction kettle is cooled to room temperature, materials in the reaction kettle are filtered, a filter cake and filtrate are collected, the filter cake is rinsed twice by using 5g of toluene, the dried recovered catalyst can be used indiscriminately, the filtrate is extracted three times by using 10g of toluene, an organic layer is taken, the toluene is recovered under the vacuum degree of 0.06MPa, 20.14g of p-chlorobenzaldehyde is obtained, 20.25g of p-chlorobenzaldehyde is obtained by measuring about 0.11g of mother liquor residue after extraction, and the molar yield is 91.18%. The reaction equation is as follows:
example 2
The difference between the present embodiment and embodiment 1 is that the molar ratio of ammonia gas to oxygen gas is 1:1.7, and the other steps are the same, thereby obtaining 20.68g of p-chlorobenzaldehyde in total and having a molar yield of 93.12%.
Example 3
The difference between this example and example 1 is that the molar ratio of ammonia to oxygen was 1:1.8, and the other steps were the same, which amounted to 20.28g, with a molar yield of 91.3%.
From the above example 1/2/3, it is understood that the molar yield to chlorobenzaldehyde is the highest when the molar ratio of ammonia gas to oxygen gas is 1:1.7, and therefore the molar ratio of ammonia gas to oxygen gas is preferably 1: 1.7.
Example 4
The difference between this method and example 2 is that the ammoxidation reaction temperature was 330 ℃ and the other steps were the same, and 19.89g of p-chlorobenzaldehyde was obtained in total in a molar yield of 89.58%.
Example 5
The difference between this embodiment and embodiment 2 is that the ammoxidation reaction temperature was 380 ℃ and the other steps were the same, and 20.11g of p-chlorobenzaldehyde was obtained in total with a molar yield of 90.57%.
From the above example 2/4/5, it is understood that the molar yield of p-chlorobenzaldehyde is highest when the temperature of the ammoxidation reaction is 350 ℃, and therefore the temperature of the ammoxidation reaction is preferably 350 ℃.
Example 6
The difference between the implementation method and the embodiment 2 is that the space velocity of p-chlorotoluene is 1.1h-1The other steps are the same, and the total amount of the p-chlorobenzaldehyde is 20.38g, and the molar yield is 91.77%.
Example 7
The difference between the implementation method and the embodiment 2 is that the space velocity of p-chlorotoluene is 1.3h-1The other steps are the same, and the total amount of the p-chlorobenzaldehyde is 19.66g, and the molar yield is 88.53%.
From the above example 2/6/7, it can be seen that the space velocity of p-chlorotoluene is 1.2h-1In this case, the molar yield of p-chlorobenzaldehyde is the highest, so that the space velocity of p-chlorotoluene is preferably 1.2h-1。
Example 8
The difference between the present embodiment and example 2 is that the temperature of the hydrolysis reaction was 80 ℃ and the other steps were the same, which gave 20.14g of p-chlorobenzaldehyde in total and a molar yield of 91.07%.
Example 9
The difference between the present embodiment and example 2 is that the temperature of hydrolysis reaction is 60 ℃, and the other steps are the same, and the total amount of p-chlorobenzaldehyde is 19.66g, and the molar yield is 88.53%.
From the above example 2/8/9, it is found that the hydrolysis reaction temperature is preferably 75 ℃ because the molar yield of p-chlorobenzaldehyde is the highest when the hydrolysis reaction temperature is 75 ℃.
Example 10
The difference between the implementation method and the embodiment 2 is that the heat preservation time of the hydrolysis reaction is 0.5h, the other steps are the same, 20.32g of p-chlorobenzaldehyde is obtained in total, and the molar yield is 91.5%.
Example 11
The difference between the method and the example 2 is that the heat preservation time of the hydrolysis reaction is 1.5h, the other steps are the same, 20.16g of p-chlorobenzaldehyde is obtained in total, and the molar yield is 91.72%.
As is clear from the above example 2/10/11, the holding time for hydrolysis is preferably 1 hour, since the molar yield of p-chlorobenzaldehyde is the highest when the holding time for hydrolysis is 1 hour.
Example 12
The difference between the present embodiment and embodiment 2 is that the molar ratio of p-chlorotoluene to ammonia gas is 1:1.3, and the other steps are the same, thus obtaining 20.67g of p-chlorobenzaldehyde in total and having a molar yield of 93.07%.
Example 13
The difference between the implementation method and the embodiment 2 is that the molar ratio of p-chlorotoluene to ammonia gas is 1:1.1, the other steps are the same, 20.06g of p-chlorobenzaldehyde is obtained in total, and the molar yield is 90.35%.
From the above example 2/12/13, it is found that the molar ratio of p-chlorotoluene to ammonia gas is preferably 1:1.2, since the molar yield of p-chlorobenzaldehyde is highest when the molar ratio of p-chlorotoluene to ammonia gas is 1: 1.2.
The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.
Claims (6)
1. A preparation method of p-chlorobenzaldehyde is characterized by comprising the following steps:
(1) and (3) oxidation reaction: filling an ammonia oxidation catalyst V into a fixed bed reactor2O5Heating, introducing nitrogen and hydrogen to make ammoxidation catalyst V2O5Activating, ammoxidation catalyst V2O5After activation, continuously introducing nitrogen for purging, introducing mixed gas of ammonia gas and oxygen gas and ammonia gas and p-chlorotoluene in advance, after the gas velocity is stable, introducing p-chlorotoluene by using a feed pump, and carrying out ammoxidation reaction to generate p-chlorobenzonitrile;
(2) and (3) hydrolysis reaction: adding parachlorobenzonitrile into a high-pressure reaction kettle, adding reduction catalysts Raney nickel and formic acid solution, replacing air in the kettle with nitrogen, filling hydrogen, heating, reacting, keeping the temperature and pressure, cooling and filtering to obtain filtrate and filter cake, extracting the filtrate with toluene, and recovering the toluene under reduced pressure to obtain parachlorobenzaldehyde; the filter cake is dried and recovered for reuse after being rinsed by toluene.
2. The method as claimed in claim 1, wherein the temperature of the oxidation reaction is 330-380 ℃.
3. The method for preparing p-chlorobenzaldehyde according to claim 1, wherein the molar ratio of ammonia to oxygen is 1: 1.6-1.8.
4. The method for preparing p-chlorobenzaldehyde according to claim 1, wherein the molar ratio of p-chlorotoluene to ammonia gas is 1: 1.1-1.3.
5. The preparation method of p-chlorobenzaldehyde according to claim 1, wherein the space velocity of p-chlorotoluene is 1.1-1.3h-1。
6. The process for preparing p-chlorobenzaldehyde according to claim 1, wherein the temperature of the hydrolysis reaction is 60 to 80 ℃.
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| CN1223579C (en) * | 2002-11-13 | 2005-10-19 | 中国石油化工股份有限公司 | Method for preparing p-chloro cyanobenzene |
| EP3057946A4 (en) * | 2013-10-17 | 2017-03-29 | Archer Daniels Midland Co. | Synthesis of diacids, dialdehydes, or diamines from thf-diols |
| CN104311376A (en) * | 2014-09-18 | 2015-01-28 | 东南大学 | New method for directly preparing aryl aldehyde from aryl nitrile |
| CN107413372B (en) * | 2017-07-03 | 2020-06-09 | 中国石油化工股份有限公司 | Fluidized bed catalyst for producing halogenated aromatic nitrile and using method thereof |
| CN109847772B (en) * | 2018-12-17 | 2022-02-18 | 中南民族大学 | Special catalyst for preparing parachlorobenzonitrile by ammoxidation method, preparation method and application |
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