CN109912424B - Method for hydrolyzing nitroaniline substances into phenol - Google Patents

Abstract

The invention discloses a method for hydrolyzing nitroaniline substances into phenol, which sequentially comprises the following steps: mixing nitroaniline substances serving as raw materials, a catalyst, inorganic base and water serving as a solvent, adding the mixture into a reaction kettle, sealing, and heating to 100-190 ℃ for reaction for 2-8 hours; and cooling the obtained reaction liquid to room temperature, then adjusting the pH value to 1-2, washing the obtained precipitate with water, and drying to obtain the nitrophenol substance as the product. The method for synthesizing the nitrophenol substance has high utilization rate of raw materials, avoids the use of high catalysts, reduces the discharge of three wastes and the production cost, and has high product purity, high yield and good industrial application value.

Description

Method for hydrolyzing nitroaniline substances into phenol

Technical Field

The invention belongs to the field of chemical industry, and relates to a method for hydrolyzing nitroaniline substances into phenol.

Background

The 2-chloro-4-nitrophenol is an important fine chemical intermediate and is widely applied in the industries of biology, medicine and the like, the fluorine-containing alkyl is introduced into phenolic hydroxyl to be used as an insecticide, and the alkynyl is introduced onto a benzene ring to be used as a cytotoxin inhibitor.

The existing 2-chloro-4-nitrophenol synthesis method mainly comprises the following steps:

1) and a chlorination method:

the p-nitrophenol is taken as a raw material and is prepared by chlorination, and the reaction formula is as follows:

CN103130657 uses chlorine as chlorine source, and directly performs chlorination reaction with p-nitrophenol in an organic solvent, and after the chlorination reaction is finished, the solvent is removed, and then recrystallization is performed to obtain 2-chloro-4-nitrophenol.

DE3810381 uses formic acid as solvent and chlorine gas is introduced at a certain temperature to synthesize 2-chloro-4-nitrophenol. The chlorine gas used as a chlorine source has the defects of strong corrosivity, high toxicity, high requirement on reaction equipment and the like.

RU2268877 uses hydrochloric acid as a solvent, and sodium hypochlorite is added dropwise to p-nitrophenol at a certain temperature to synthesize 2-chloro-4-nitrophenol. The method has the problems of more dichloro byproducts (2, 6-dichloro-4-nitrophenol), low product purity and the like.

CN1282730 uses hydrochloric acid as solvent, and adds potassium chloride solution at a certain temperature to synthesize 2-chloro-4-nitrophenol. The potassium chlorate used by the method has high cost and strong chloridizing capability, and is easy to generate polychlorinated side reaction.

The literature, Pharmaceutical Chemistry Journal,2000,34(4):215-216, uses p-nitrophenol as raw material, and performs chlorination in hydrogen peroxide/hydrochloric acid system to obtain 2-chloro-4-nitrophenol. The method has the problems of low yield, high danger of hydrogen peroxide and the like.

2) And a hydrolysis method:

the document application chemical industry, 2007,36(12),1249-1521, takes 3, 4-dichloronitrobenzene as raw material, and carries out alkaline hydrolysis under high pressure condition to synthesize 2-chloro-4-nitrophenol, the reaction formula is as follows:

the method has the problems of low product yield, poor purity and the like.

3) And a nitration method:

the method is characterized in that 2-chlorophenol is used as a raw material and is prepared by nitration, and the reaction formula is as follows:

the literature Synthesis and reaction in Organic, Metal-Organic, and Nano-Metal Chemistry,2014,44(3):364,370 nitrifies 2-chlorophenol with Prussian blue as nitrating agent in a yield of 92%.

The Arabidopsis Journal of Chemistry,2017,10(Supp1),509-513 employed melamine trisulfonic acid as a catalyst, sodium nitrate as a nitrating agent, and the yield of 2-chloro-4-nitrophenol was 88%.

The traditional nitration method has more side reactions (2-chloro-6-dinitrophenol and 2-chloro-5-nitrophenol), and the nitrating agent and the catalyst reported in the literature are expensive and difficult to be applied industrially.

The document J.org.chem.2011,76, 6356-. When 4-nitroaniline serving as a substrate is used as a raw material and reacts with an aqueous solution of sodium hydroxide at 150 ℃ for 0.1 hour, the yield of 4-nitrophenol is 100%, but when the derivative contains halogen atoms, the problems of poor reaction selectivity, long reaction time and the like exist, for example, after 3-chloro-6-nitroaniline is hydrolyzed in the aqueous solution of sodium hydroxide for 50 hours, various hydrolysis products are generated, wherein the 3-chloro-6-nitroaniline only accounts for 68%, and the method has narrow applicability.

In addition, there is a document that aniline derivatives are used as a substrate, and corresponding phenol is synthesized through diazotization and hydrolysis. The diazotization method has the problems of complex operation, more byproducts, large pollution and the like, and the 2-chloro-4-nitrophenol is not synthesized by taking 2-chloro-4-nitroaniline as a raw material through the diazotization method at present.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a method for hydrolyzing nitroaniline into phenol, which is efficient, economic and suitable for industrial production requirements.

In order to solve the technical problem, the invention provides a method for hydrolyzing nitroaniline substances into phenol, which sequentially comprises the following steps:

1) mixing nitroaniline substances serving as raw materials, a catalyst, inorganic base and water serving as a solvent, adding the mixture into a reaction kettle, sealing, heating to 100-190 ℃, reacting for 2-8 hours,

alkali: nitroaniline substances are 1-1.5: 1, the catalyst is 5-20 wt% of nitroaniline;

the catalyst is polyethylene glycol with the molecular weight of 200-1000;

2) and cooling the reaction solution obtained in the step 1) to room temperature, then adjusting the pH value to 1-2, and washing and drying the obtained precipitate (crude product of nitrophenol substances) to obtain the nitrophenol substances serving as the product.

The improvement of the method for hydrolyzing the nitroaniline substances into phenol comprises the following steps: the inorganic alkali is potassium hydroxide or sodium hydroxide.

As a further improvement of the process for the hydrolysis of nitroanilides to phenols according to the invention: in the step 1), 200-400 ml (preferably 300-400 ml) of water is added to 1mol of nitroaniline substance.

As a further improvement of the process according to the invention for hydrolyzing nitroanilides to phenols, in step 1):

the reaction temperature is 150-190 ℃, the reaction time is 4-6 h,

alkali: nitroaniline substances are 1.2-1.5: the molar ratio of 1 is determined by the following formula,

the catalyst is 8-15 wt% of nitroaniline substances,

the molecular weight of the polyethylene glycol is 200-400.

As a further improvement of the process according to the invention for hydrolyzing nitroanilides to phenols, the acid used for pH adjustment in step 2) is an inorganic acid, for example sulfuric acid (preferably a 20% sulfuric acid solution), hydrochloric acid.

As a further improvement of the process according to the invention for the hydrolysis of nitroanilides to phenols,

when the raw material is 2-chloro-4-nitroaniline, the product is 2-chloro-4-nitrophenol;

when the raw material is 2-nitro-5-chloroaniline, the product is 2-nitro-5-chlorophenol;

when the raw material is 3-chloro-4-nitroaniline, the product is 3-chloro-4-nitrophenol.

In the present invention,

the reaction equation for 2-chloro-4-nitrophenol is:

the reaction equation of 2-nitro-5-chlorophenol is:

the reaction equation for 3-chloro-4-nitrophenol is:

the method for hydrolyzing the nitroaniline substances into phenol has the following technical advantages:

1) at present, no synthetic process report for preparing 2-chloro-4-nitrophenol by directly hydrolyzing 2-chloro-4-nitroaniline serving as a raw material exists.

2) The raw materials, alkali metal and catalyst are cheap and easy to obtain, and the reaction solvent is water, so that the method is green and environment-friendly; the use of complex catalysts is not needed, the process steps are simple, and the product post-treatment is convenient.

3) The nitrophenol substance synthesized by the method has high purity and high yield. The yield of the 2-chloro-4-nitrophenol obtained by the method can reach 82.6 percent, and the purity can reach 99 percent.

In conclusion, the nitrophenol substance synthesized by the method has high utilization rate of raw materials, avoids the use of high catalysts, reduces the discharge of three wastes and the production cost, and has high product purity, high yield and good industrial application value.

Drawings

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

FIG. 1 is a mass spectrum of 2-chloro-4-nitrophenol obtained in the present invention;

FIG. 2 is the molecular structural formula of the 2-chloro-4-nitrophenol obtained by the invention.

Detailed Description

The invention will be further described with reference to specific examples, but the scope of the invention is not limited thereto:

examples 1,

86.3g (0.5mol) of the raw material 2-chloro-4-nitroaniline, 33.7g (0.6mol) of potassium hydroxide, 150ml of deionized water and 10g of polyethylene glycol (PEG400) are mixed and added into a reaction kettle. The reaction kettle is sealed after air is replaced by nitrogen for many times, and the temperature is raised to 150 ℃ and kept for 4 hours.

After the reaction is finished, the reaction kettle is cooled to room temperature and then opened, the pH of the reaction liquid is adjusted to 2 by using 20 percent (volume percent) sulfuric acid, so that crude 2-chloro-4-nitrophenol is separated out, the crude 2-chloro-4-nitrophenol is filtered, a filter cake is washed three times by using deionized water (the using amount of the deionized water for washing each time is 30ml), and then the filter cake is dried (dried to constant weight at 80 ℃) to obtain 71.7g of 2-chloro-4-nitrophenol (refined product), the yield is 82.6 percent, and the purity is 99 percent.

Note: when the pH was changed to 1, the yield was 82.5% and the purity was 99%.

Example 2, the process of example 1 was repeated except that "33.7 g (0.6mol) of potassium hydroxide" was changed to "24 g (0.6mol) of sodium hydroxide", and the process was identical to that of example 1.

The yield of the obtained 2-chloro-4-nitrophenol is 80.6 percent, and the purity is 99 percent.

Example 3-1 to example 3-4, the amount of 2-chloro-4-nitroaniline was kept constant, only the reaction temperature in example 1 was changed, and the remaining conditions were the same as those in example 1; the specific process parameters and the obtained results are shown in the following table 1; the purity of the obtained 2-chloro-4-nitrophenol is 99 percent.

TABLE 1

Examples	Reaction temperature/. degree.C	Yield/%
			3-1	100	76.2
3-2	120	78.3
			3-3	170	82.5
3-4	190	82.6

Example 4-1 to example 4-4, keeping the charge of 2-chloro-4-nitroaniline constant, only changing the amount of the base used in example 1, thereby correspondingly changing the molar ratio of the base to the 2-chloro-4-nitroaniline, and the rest conditions are identical to those in example 1; the specific process parameters and the obtained results are shown in the following table 2; the purity of the obtained 2-chloro-4-nitrophenol is 99 percent.

TABLE 2

Example 5-1 to example 5-4, the amount of 2-chloro-4-nitroaniline used was changed to the same amount as in example 1 except that the amount of polyethylene glycol (PEG400) used was changed, and the remaining conditions were the same as in example 1. The specific process parameters and the obtained results are shown in table 3 below; the purity of the obtained 2-chloro-4-nitrophenol is 99 percent.

TABLE 3

Example 6-1 to example 6-3, the type of the polyethylene glycol in example 1 was changed while keeping the amount of the 2-chloro-4-nitroaniline added, and the remaining conditions were the same as those in example 1; the specific process parameters and the results are shown in table 4 below; the purity of the obtained 2-chloro-4-nitrophenol is 99 percent.

TABLE 4

Examples	Polyethylene glycol species	Yield/%
			6-1	PEG200	82.4
6-2	PEG600	80.2
			6-3	PEG1000	76.6

Example 7-1 to example 7-4, the amount of 2-chloro-4-nitroaniline was kept constant, only the amount of water used in example 1 was changed, and the remaining conditions were the same as those in example 1; the specific process parameters and the results are shown in table 5 below; the purity of the obtained 2-chloro-4-nitrophenol is 99 percent.

TABLE 5

Examples	Amount of water used/ml	Yield/%
			7-1	100	72.5
7-2	130	79.1
			7-3	180	82.5
7-4	200	82.6

Example 8-1 to example 8-3, the amount of 2-chloro-4-nitroaniline was kept constant, only the reaction time in example 1 was changed, and the remaining conditions were the same as those in example 1; the specific process parameters and the results are shown in table 6 below; the purity of the obtained 2-chloro-4-nitrophenol is 99 percent.

TABLE 6

Examples	Reaction time/h	Yield/%
			8-1	2	79.6
8-2	6	82.6
			8-3	8	82.6

Examples 9,

0.5mol of raw material 2-nitro-5-chloroaniline, 0.6mol of potassium hydroxide, 150ml of deionized water and 10g of polyethylene glycol (PEG400) are mixed and added into a reaction kettle. The reaction kettle is sealed after air is replaced by nitrogen for many times, and the temperature is raised to 150 ℃ and kept for 4 hours.

After the reaction is finished, the reaction kettle is cooled to room temperature and then opened, the pH value of reaction liquid is adjusted to 2 by using 20% sulfuric acid, so that crude 2-nitro-5-chlorophenol is separated out, the crude 2-nitro-5-chlorophenol is filtered, a filter cake is washed three times by using deionized water (the using amount of the deionized water for each washing is 30ml), and then the filter cake is dried (dried to constant weight at 80 ℃) to obtain 70.2g of 2-nitro-5-chlorophenol (refined product), the yield is 80.9%, and the purity is 99%.

Examples 10,

Taking 0.5mol of raw material 3-chloro-4-nitroaniline, 0.6mol of potassium hydroxide, 150ml of deionized water and 10g of polyethylene glycol (PEG400), mixing, and adding into a reaction kettle. The reaction kettle is sealed after air is replaced by nitrogen for many times, and the temperature is raised to 150 ℃ and kept for 4 hours.

After the reaction is finished, the reaction kettle is cooled to room temperature and then opened, the pH of the reaction liquid is adjusted to 2 by using 20% sulfuric acid, so that crude 3-chloro-4-nitrophenol is separated out, the crude 3-chloro-4-nitrophenol is filtered, a filter cake is washed three times by using deionized water (the using amount of the deionized water for each washing is 30ml), and then the filter cake is dried (dried to constant weight at 80 ℃) to obtain 71.2g of 3-chloro-4-nitrophenol (refined product), the yield is 82.1%, and the purity is 99%.

Comparative example 1, with respect to example 1, only the pH value adjusted in the reaction solution of example 1 was changed, and the remaining conditions were the same as those of example 1; the specific process parameters and the results are shown in table 7 below;

TABLE 7

pH value	Yield/%	Purity/%)
			3	45.4	99
4	29.6	99

Comparative example 2, the catalyst in example 1 was changed (or the use of the catalyst was eliminated) with respect to example 1, and the remaining conditions were identical to those of example 1; the specific process parameters and the results obtained are shown in table 8 below in comparison with example 1;

TABLE 8

Comparative example 3, relative to example 1, the solvent was changed from water to sulfolane or methanol, respectively; the rest is equivalent to embodiment 1. The results obtained were: the reaction was not carried out efficiently, and the yield was 0.

Comparative example 4, change the catalyst in example 9 (or eliminate the use of catalyst) relative to example 9, with/without corresponding change in reaction time, the remaining conditions being identical to those of example 9; specific process parameters and results are shown in table 9 below for example 9;

TABLE 9

Comparative example 5, change the catalyst (or eliminate the use of catalyst) in example 10 relative to example 10, with/without corresponding change in reaction time, the remaining conditions being identical to those of example 10; the specific process parameters and results are shown in table 10 below for example 10;

watch 10

Finally, it is also noted that the above-mentioned lists merely illustrate a few specific embodiments of the invention. It is obvious that the invention is not limited to the above embodiments, but that many variations are possible. All modifications which can be derived or suggested by a person skilled in the art from the disclosure of the present invention are to be considered within the scope of the invention.

Claims (7)

1. The method for hydrolyzing the nitroaniline substances into the phenol is characterized by sequentially comprising the following steps of:

1) mixing nitroaniline substances serving as raw materials, a catalyst, inorganic base and water serving as a solvent, adding the mixture into a reaction kettle, sealing, heating to 100-190 ℃, reacting for 2-8 hours,

alkali: nitroaniline substances are 1-1.5: 1, the catalyst is 5-20 wt% of nitroaniline;

the catalyst is polyethylene glycol with the molecular weight of 200-1000;

the nitroaniline substances as raw materials are 2-chloro-4-nitroaniline, 2-nitro-5-chloroaniline or 3-chloro-4-nitroaniline;

2) and cooling the reaction liquid obtained in the step 1) to room temperature, then adjusting the pH value to 1-2, washing the obtained precipitate with water, and drying to obtain the nitrophenol substance serving as the product.

2. The method of hydrolyzing nitroanilides to phenols according to claim 1, wherein: the inorganic alkali is potassium hydroxide or sodium hydroxide.

3. A method according to claim 1 or 2, characterized in that the nitroanilides are hydrolyzed to phenols: in the step 1), 200-400 ml of water is added to 1mol of nitroaniline substance.

4. The method for synthesizing 2-chloro-4-nitrophenol according to claim 3, wherein in the step 1):

the reaction temperature is 150-190 ℃, the reaction time is 4-6 h,

alkali: nitroaniline substances are 1.2-1.5: the molar ratio of 1 is determined by the following formula,

the catalyst is 8-15 wt% of nitroaniline substances,

the molecular weight of the polyethylene glycol is 200-400.

5. The process for the synthesis of 2-chloro-4-nitrophenol as claimed in claim 3, characterized in that: in the step 2), the acid used for adjusting the pH is an inorganic acid.

6. The method for synthesizing 2-chloro-4-nitrophenol according to claim 5, wherein: the inorganic acid is sulfuric acid or hydrochloric acid.

7. The method for synthesizing 2-chloro-4-nitrophenol according to claim 1, wherein:

when the raw material is 2-chloro-4-nitroaniline, the product is 2-chloro-4-nitrophenol;

when the raw material is 2-nitro-5-chloroaniline, the product is 2-nitro-5-chlorophenol;

when the raw material is 3-chloro-4-nitroaniline, the product is 3-chloro-4-nitrophenol.

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