CN117903011A - A method for continuously preparing 4-chlorobenzenesulfonic acid - Google Patents

Abstract

The invention discloses a method for continuously preparing 4-chlorobenzenesulfonic acid, which comprises the following specific steps of: step one, dissolving sulfur trioxide in chloroform to prepare a 20% sulfur trioxide solution; step two, mixing a 20% sulfur trioxide solution with 99% of chlorobenzene in mass concentration to obtain a mixed solution; and thirdly, preparing the 4-chlorobenzenesulfonic acid through temperature control and stirring reaction of the mixed solution in n-level continuous reaction equipment. The invention has the following beneficial effects: the conversion rate of the chlorobenzene is about 99% and the molar yield of the 4-chlorobenzenesulfonic acid product can reach more than 92% by directionally selecting the halogenated hydrocarbon to be trichloromethane and then using a continuous reaction device to select other halogenated hydrocarbons in a contrasting way.

Description

A method for continuously preparing 4-chlorobenzenesulfonic acid

Technical Field

The invention relates to the technical field of organic synthesis, and in particular to a method for continuously preparing 4-chlorobenzenesulfonic acid.

Background technique

4-Chlorobenzenesulfonic acid is an important organic synthesis intermediate of p-chlorobenzenesulfonyl chloride, which is widely used in dye, medicine and other industries. It is also an important raw material for synthesizing chemical intermediate 4,4'-dichlorodiphenyl sulfone. p-Chlorobenzenesulfonic acid is light yellow needle-shaped crystals at room temperature, with a pungent odor, deliquescent, soluble in water, slightly soluble in ethanol, and insoluble in chlorobenzene.

At present, the industrial production of 4-chlorobenzenesulfonic acid is mostly carried out in an intermittent manner. Workers participate in the production process many times, and each batch reaction requires repeated feeding, reaction, and discharging. It is easy to make mistakes in operation, and the production process cannot be well controlled, resulting in high production costs.

In summary, the intermittent production method in the prior art has the following defects: 1) manual feeding during the production process, which is inefficient; 2) low yield.

Therefore, it is urgent to provide a method for continuously preparing 4-chlorobenzenesulfonic acid to solve the above problems.

Summary of the invention

The technical problems to be solved by the present invention are:

A method for continuously preparing 4-chlorobenzenesulfonic acid is developed, and the method for continuously preparing 4-chlorobenzenesulfonic acid has the characteristics of improved efficiency and high yield.

The purpose of the present invention is to solve the problems existing in the above-mentioned prior art conditions and to provide a method for continuously preparing 4-chlorobenzenesulfonic acid.

In order to achieve the above object, the present invention adopts the following technical solutions:

A method for continuously preparing 4-chlorobenzenesulfonic acid, wherein 4-chlorobenzenesulfonic acid is prepared by continuous equipment, and the specific steps are as follows:

step one

Dissolve sulfur trioxide in halogenated hydrocarbon to prepare a 20% sulfur trioxide solution;

Step 2

Mixing a 10% to 99% sulfur trioxide solution with 99% chlorobenzene by mass concentration to obtain a mixed solution;

Step 3

The 4-chlorobenzenesulfonic acid is prepared by subjecting the mixed liquid to temperature control and stirring reaction in an n-stage continuous reaction device.

As a further improvement of this scheme,

The continuous reaction equipment comprises a mixing pump (10), a circulation pump (20), a retention kettle (30), and a discharge pump (40) which are arranged in sequence;

Wherein, chlorobenzene is transported to a mixing pump (10) and a sulfonation retention reactor (31) through pipelines respectively;

The sulfur trioxide solution is transported to the mixing pump (10) and the sulfonation retention reactor (31) through pipelines;

The mixing pump is provided with a pipeline connected to the sulfonation retention reactor 1 (31);

The circulation pump (20) is provided with a pipeline for returning to the mixing pump;

A pipeline for reflux to a circulation pump (20) is provided at the bottom of the sulfonation retention reactor 1 (31);

The sulfonation retention kettle (30) further comprises a plurality of kettle bodies connected in series, and the kettle body at the end is connected to the discharge pump (40).

As a further improvement of this scheme,

The sulfonation retention kettle (30) further comprises at least a sulfonation retention kettle 1 (31), a sulfonation retention kettle 2 (32), a sulfonation retention kettle 3 (33), and a sulfonation retention kettle 4 (34).

Furthermore, a stirring paddle is provided in the sulfonation retention kettle (30).

As a further improvement of this solution, step 3 further includes:

S31 sulfur trioxide solution and 99% chlorinated benzene are transported to the mixing pump and mixed and reacted in the mixing pump;

S32 flows into the sulfonation retention kettle (31) from the top inlet of the sulfonation retention kettle (31) for stirring reaction; at the same time, the reaction liquid in the first-stage sulfonation retention kettle (31) is divided into two outflows, one of which is returned to the mixing pump (10) through the circulation pump (20) to repeat the sulfonation reaction, and the other is continuously fed from the second-stage sulfonation retention kettle (32) through the third-stage sulfonation retention kettle (33) in sequence, and then flows to the fourth-stage sulfonation retention kettle (34);

The reaction liquid in the fourth-stage sulfonation retention kettle (34) is pumped out by a discharge pump (40), recrystallized by a water solvent, centrifuged, and dried to obtain a 4-chlorobenzenesulfonic acid product;

The reaction temperature is controlled at about 15-20°C, and the total residence time of the reaction liquid in the four-stage sulfonation residence kettle connected in series is about 2 hours.

As a further improvement of this solution, the feed mass ratio of sulfur trioxide, halogenated hydrocarbon and chlorinated benzene is 1:0-5:0.7-1.7.

As a further improvement of this solution, the feed mass ratio of sulfur trioxide, halogenated hydrocarbon and chlorinated benzene is 1:3:1.5.

As a further improvement of this solution, the auxiliary agent used for crystallization is any one or more of water, ethanol, and isopropanol.

As a further improvement of this solution, n is an integer from 2 to 8.

As a further improvement of this solution, n is an integer from 2 to 8.

Compared with the prior art, the present invention has the following beneficial effects:

1) The method of the present invention can realize the continuous industrial production of 4-chlorobenzenesulfonic acid. The sulfur trioxide solution and chlorobenzene first flow into a mixing pump for forced mixing reaction, thereby accelerating the reaction speed;

2) Furthermore, the reaction liquid flowing out of the mixing pump flows into the n-stage sulfonation retention kettle connected in series to be stirred, and the reaction liquid in the first-stage sulfonation retention kettle is partially refluxed into the mixing pump to continue the reaction. This process has the following two advantages: 1. The setting of the n-stage sulfonation retention kettle connected in series increases the reaction time and makes the sulfonation reaction more thorough; 2. It is easy to remove a large amount of heat generated by the reaction, avoid overheating of the reaction temperature and improve the safety of the reaction;

3) The present invention introduces more control instruments and adopts DCS control to realize the industrial production of 4-chlorobenzenesulfonic acid under industrial automation control, reduces the operation of manual participation, and the raw material input ratio, raw material input amount and reaction time can be accurately controlled, making the industrial production process safer and more reliable;

4) In the present invention, chloroform is selected as the halogenated hydrocarbon by orientation, and then a continuous reaction device is used, so that compared with other halogenated hydrocarbons, the conversion rate of chlorobenzene in the present invention is about 99%, and the molar yield of 4-chlorobenzenesulfonic acid product can reach more than 92%.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the structure of a continuous equipment in the method for continuously preparing 4-chlorobenzenesulfonic acid of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention is further described below in conjunction with embodiments:

Embodiment 1:

The structural schematic diagram of the reaction device for continuously preparing 4-chlorobenzenesulfonic acid in this embodiment 1 is shown in Figure 1. As can be seen from Figure 1, the reaction device includes 4 stages of sulfonation retention kettles, mixing pumps, circulating pumps and discharge pumps connected in series in sequence. The liquid outlet of the mixing pump is connected to the top liquid inlet of the first-stage sulfonation retention kettle 1 by a pipeline, and the bottom liquid outlet of the first-stage sulfonation retention kettle 1 is connected to the liquid inlet of the mixing pump by a pipeline through the circulating pump, forming a partial internal circulation of the reaction liquid. The middle liquid outlet of the first-stage sulfonation retention kettle 1 is connected to the top liquid inlet of the second-stage sulfonation retention kettle 2 by a pipeline, the middle liquid outlet of the second-stage sulfonation retention kettle 2 is connected to the top liquid inlet of the third-stage sulfonation retention kettle 3 by a pipeline, and the middle liquid outlet of the third-stage sulfonation retention kettle 3 is connected to the top liquid inlet of the fourth-stage sulfonation retention kettle 4 by a pipeline, thereby forming 4 stages of sulfonation retention kettles connected in series in sequence, and control valves are provided on the corresponding pipelines;

Dissolve sulfur trioxide in chloroform to prepare a 20% sulfur trioxide solution for later use;

The sulfur trioxide solution and chlorobenzene with a mass concentration of 99% are transported to a mixing pump together and mixed and reacted by the mixing pump (the mass ratio of sulfur trioxide, chloroform and chlorobenzene is 1:4:1.5), and then flow into the first-stage sulfonation retention kettle 1 from the top inlet of the first-stage sulfonation retention kettle 1 for stirring reaction; at the same time, the reaction liquid in the first-stage sulfonation retention kettle 1 is divided into two outflows, one of which is returned to the mixing pump through a circulation pump to repeat the sulfonation reaction, and the other is flowed from the second-stage sulfonation retention kettle 2 to the fourth-stage sulfonation retention kettle in a continuous feeding manner. The reaction liquid in the fourth-stage sulfonation retention kettle is pumped out by a discharge pump, recrystallized by a water solvent, centrifuged, and dried to obtain a 4-chlorobenzenesulfonic acid product. The reaction temperature is controlled at about 15-20°C, and the total residence time of the reaction liquid in the mixing pump and the 4-stage sulfonation retention kettles connected in series is about 2h.

When the reaction is substantially complete (i.e., the conversion rate of chlorobenzene reaches 99% or more), the molar yield of 4- chlorobenzenesulfonic acid product can reach 92% or more. The quality index of the final 4-chlorobenzenesulfonic acid product is as follows : 4-chlorobenzenesulfonic acid mass fraction ≥ 99% .

Embodiment 2:

The structural schematic diagram of the reaction device for continuously preparing 4-chlorobenzenesulfonic acid in this embodiment 2 is shown in Figure 1. As can be seen from Figure 1, the reaction device includes 4 stages of sulfonation retention kettles, mixing pumps, circulating pumps and discharge pumps connected in series in sequence. The liquid outlet of the mixing pump is connected to the top liquid inlet of the first-stage sulfonation retention kettle 1 by a pipeline, and the bottom liquid outlet of the first-stage sulfonation retention kettle 1 is connected to the liquid inlet of the mixing pump by a pipeline through the circulating pump, forming a partial internal circulation of the reaction liquid. The middle liquid outlet of the first-stage sulfonation retention kettle 1 is connected to the top liquid inlet of the second-stage sulfonation retention kettle 2 by a pipeline, the middle liquid outlet of the second-stage sulfonation retention kettle 2 is connected to the top liquid inlet of the third-stage sulfonation retention kettle 3 by a pipeline, and the middle liquid outlet of the third-stage sulfonation retention kettle 3 is connected to the top liquid inlet of the fourth-stage sulfonation retention kettle 4 by a pipeline, thereby forming 4 stages of sulfonation retention kettles connected in series in sequence, and control valves are provided on the corresponding pipelines;

Dissolve sulfur trioxide in chloroform to prepare a 25% sulfur trioxide solution for later use;

The sulfur trioxide solution and chlorobenzene with a mass concentration of 99% are transported to a mixing pump together and mixed and reacted by the mixing pump (the mass ratio of sulfur trioxide, chloroform and chlorobenzene is 1:3:1.6), and then flow into the first-stage sulfonation retention kettle 1 from the top inlet of the first-stage sulfonation retention kettle 1 for stirring reaction; at the same time, the reaction liquid in the first-stage sulfonation retention kettle 1 is divided into two outflows, one of which is returned to the mixing pump through a circulation pump to repeat the sulfonation reaction, and the other is flowed from the second-stage sulfonation retention kettle 2 to the fourth-stage sulfonation retention kettle in a continuous feeding manner. The reaction liquid in the fourth-stage sulfonation retention kettle is pumped out by a discharge pump, recrystallized by a water solvent, centrifuged, and dried to obtain a 4-chlorobenzenesulfonic acid product. The reaction temperature is controlled at about 15-20°C, and the total residence time of the reaction liquid in the four-stage sulfonation retention kettles connected in series is about 2h.

By adopting the above production process, the conversion rate of chlorobenzene is about 99%, and the molar yield of 4-chlorobenzenesulfonic acid product can reach about 90%.

Comparative Example 1:

This example provides a preparation method of 4-chlorobenzenesulfonic acid, which is basically the same as the steps in Example 1, except that: the mixing pump and the circulating pump are not turned on; the sulfur trioxide solution and the chlorobenzene with a mass concentration of 99% flow into the first-stage sulfonation retention kettle 1 from the top inlet of the first-stage sulfonation retention kettle 1 for stirring reaction; and flow from the first-stage nitration retention kettle 1 to the fourth-stage nitration retention kettle in a continuous feeding manner, and the reaction liquid in the fourth-stage sulfonation retention kettle is pumped out by a discharge pump, recrystallized by a water solvent, centrifuged, and dried to obtain a 4-chlorobenzenesulfonic acid product; the total residence time of the reaction liquid in the four-stage sulfonation retention kettles connected in series is about 6 hours.

By adopting the above production process, the conversion rate of chlorobenzene is about 96%, and the molar yield of 4-chlorobenzenesulfonic acid product can reach about 80%.

It can be seen from the reaction results of Example 1 and Comparative Example 1 that 4-chlorobenzenesulfonic acid can be continuously prepared by the method of the present invention, and a good reaction effect can be obtained. Moreover, relative to Comparative Example 1, the method of Example 1 achieves a better reaction effect and greatly shortens the reaction time. This may be because when the reaction apparatus of Example 1 is used to continuously prepare 4-chlorobenzenesulfonic acid, the mixing pump can effectively strengthen the sulfonation reaction process, and the residence time of the reaction solution in the mixing pump is short. The reaction solution after forced mixing by the mixing pump flows into the sulfonation retention kettle, which is easy to remove a large amount of heat generated by the reaction, and avoids overheating of the reaction temperature.

Comparative Example 2:

This example provides a method for preparing 4-chlorobenzenesulfonic acid, which is basically the same as the steps in Example 2, except that chloroform is replaced by trichloroethane.

By adopting the above production process, the conversion rate of chlorobenzene is about 82%, and the molar yield of 4-chlorobenzenesulfonic acid product can reach about 69%.

The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent changes made using the present invention are within the patent protection scope of the present invention.

Claims (9)

1. A method for continuously preparing 4-chlorobenzenesulfonic acid, characterized in that: 4-Chlorobenzenesulfonic acid is prepared by continuous equipment, and the specific steps are as follows: step one Dissolving sulfur trioxide in halogenated hydrocarbons to prepare a 10% to 99% sulfur trioxide solution; Step 2 Mixing a 10% to 99% sulfur trioxide solution with 99% chlorobenzene by mass concentration to obtain a mixed solution; Step 3 The 4-chlorobenzenesulfonic acid is prepared by subjecting the mixed liquid to temperature control and stirring reaction in an n-stage continuous reaction device. 2. The method for continuously preparing 4-chlorobenzenesulfonic acid according to claim 1, characterized in that: The continuous reaction equipment comprises a mixing pump (10), a circulation pump (20), a retention kettle (30), and a discharge pump (40) which are arranged in sequence; Wherein, chlorobenzene is transported to a mixing pump (10) and a sulfonation retention reactor (31) through pipelines respectively; The sulfur trioxide solution is transported to the mixing pump (10) and the sulfonation retention reactor (31) through pipelines; The mixing pump is provided with a pipeline connected to the sulfonation retention reactor 1 (31); The circulation pump (20) is provided with a pipeline for returning to the mixing pump; A pipeline for reflux to a circulation pump (20) is provided at the bottom of the sulfonation retention reactor 1 (31); The sulfonation retention kettle (30) further comprises a plurality of kettle bodies connected in series, and the kettle body at the end is connected to the discharge pump (40). 3. The method for continuously preparing 4-chlorobenzenesulfonic acid according to claim 2, characterized in that: The sulfonation retention kettle (30) further comprises at least a sulfonation retention kettle 1 (31), a sulfonation retention kettle 2 (32), a sulfonation retention kettle 3 (33), and a sulfonation retention kettle 4 (34). Furthermore, a stirring paddle is provided in the sulfonation retention kettle (30). 4. The method for continuously preparing 4-chlorobenzenesulfonic acid according to claim 3, characterized in that the step 3 further comprises: S31 sulfur trioxide solution and 99% chlorinated benzene are transported to the mixing pump and mixed and reacted in the mixing pump; S32 flows into the sulfonation retention kettle (31) from the top inlet of the sulfonation retention kettle (31) for stirring reaction; at the same time, the reaction liquid in the first-stage sulfonation retention kettle (31) is divided into two outflows, one of which is returned to the mixing pump (10) through the circulation pump (20) to repeat the sulfonation reaction, and the other is continuously fed from the second-stage sulfonation retention kettle (32) through the third-stage sulfonation retention kettle (33) in sequence, and then flows to the fourth-stage sulfonation retention kettle (34); The reaction liquid in the fourth-stage sulfonation retention kettle (34) is pumped out by a discharge pump (40), recrystallized by a water solvent, centrifuged, and dried to obtain a 4-chlorobenzenesulfonic acid product; The reaction temperature is controlled at about 15-20°C, and the total residence time of the reaction liquid in the four-stage sulfonation residence kettle connected in series is about 2 hours. 5. The method for continuously preparing 4-chlorobenzenesulfonic acid according to claim 1, characterized in that the feed mass ratio of sulfur trioxide, halogenated hydrocarbon and chlorobenzene is 1:0-5:0.7-1.7. 6. A method for continuously preparing 4-chlorobenzenesulfonic acid according to claim 1, characterized in that the feed mass ratio of sulfur trioxide, halogenated hydrocarbon and chlorobenzene is 1:3:1.5. 7. The method for continuously preparing 4-chlorobenzenesulfonic acid according to claim 1, characterized in that the auxiliary agent used for crystallization is any one or more of water, ethanol, and isopropanol. 8. The method for continuously preparing 4-chlorobenzenesulfonic acid according to claim 1, wherein n is an integer of 2 to 8. 9. The method for continuously preparing 4-chlorobenzenesulfonic acid according to claim 1, characterized in that, n is an integer of 2 to 8.