Continuous production system for tetrabutylurea, centralite I and centralite II

Abstract

The utility model discloses a continuous production system for tetrabutylurea, centralite I and centralite II, which is characterized in that a main raw material inlet pipeline and a gas outlet pipeline are arranged on a main raw material vaporizer, and a phosgene inlet pipe and a main raw material gas inlet pipe are arranged at the top of a gas reactor; a main raw material gas inlet pipe is connected with a gas outlet pipeline of the main raw material vaporizer, a discharge port at the bottom of the gas reactor is connected with a condenser, the condenser is connected with a receiving tank, and a hydrogen chloride discharge pipe is arranged on the receiving tank; a sodium hydroxide solution adding pipeline, a main raw material adding pipeline and an intermediate acyl chloride adding pipeline or a dropping funnel are arranged on the reaction kettle, and the intermediate acyl chloride adding pipeline or the dropping funnel is connected with the receiving tank. And the generation of wastewater is reduced. Through the method, the final yield is greater than 95%, and the yield is high. The reaction time of the second step is shortened by about one third, and the overall efficiency is improved.

Description

Technical Field

[0001] The utility model relates to a continuous production system for tetrabutylurea, stabilizer No. I and stabilizer No. II, belonging to the field of chemical production. Background Art

[0002] Tetrabutylurea (C17H36N2O) is a widely used organic synthesis intermediate and can also be used as a solvent extractant and catalyst in organic chemistry, especially as a solvent in the production process of hydrogen peroxide. The methods for synthesizing tetrabutylurea generally include the phosgene method and the non-phosgene method. The phosgene method includes the monophosgene method, the diphosgene method, the triphosgene method, etc. Solvents are required in the preparation of tetrabutylurea by the diphosgene method and the triphosgene method. Although the monophosgene method does not use solvents during the reaction, benzene or toluene is needed for extraction in the subsequent treatment. According to relevant reports, the yield of the finished product is only 80%-85%. The non-phosgene method includes the carbon monoxide method, the carbon dioxide method, the acetanilide method, etc. The carbon monoxide method requires auxiliary reagents such as oxygen or potassium iodide and reacts under pressurized conditions, with low yield and many by-products. It is difficult to industrialize the reaction of dibutylaminolithium with dibutylamine and carbon monoxide. The acetanilide method reacts with dibutylamine. Although the toxicity is small, the product is an equal amount of tetrabutylurea and by-products.

[0003] The patent CN 102702029 A previously applied by the applicant discloses a preparation process for tetrabutylurea, which is synthesized from dibutylamine and carbonyl chloride as main raw materials in an alkaline organic solvent. The process steps are as follows: (1) Add dibutylamine, carbonyl chloride and an organic solvent to the reaction vessel according to the ratio; (2) Adjust the acylation reaction temperature and control the acylation reaction time to obtain crude tetrabutylurea; (3) The crude tetrabutylurea is subjected to standing, separation, distillation and purification to obtain the final product of tetrabutylurea. Since two molecules of hydrogen chloride will be generated during the reaction of dibutylamine and carbonyl chloride, a large amount of 20% sodium hydroxide solution needs to be added for neutralization during the reaction, which ultimately leads to the generation of a large amount of alkaline wastewater during treatment, increasing the production cost and the cost of wastewater treatment in the later stage.

[0004] Similarly, stabilizer No. I is synthesized by reacting N-ethylaniline with phosgene in an alkaline medium, then adding water to cool down, stirring, and a product precipitates, and then filtering to remove the sodium chloride aqueous solution.

[0005] Stabilizer No. II is synthesized by reacting N-methylaniline with phosgene in an alkaline medium, then adding water to cool down, stirring, and a product precipitates, and then filtering to remove the sodium chloride aqueous solution. The crude product obtained by filtration is added to a distillation kettle for distillation to obtain the product.

[0006] Similar to tetrabutylurea, a large amount of wastewater will also be generated during the production of stabilizer No. I and stabilizer No. II. Content of the Utility Model

[0007] In view of the above technical problems, the purpose of the present utility model is to provide a continuous production system for tetrabutylurea, stabilizer No. 1 and stabilizer No. 2, which can reduce the use of sodium hydroxide solution and the generation of waste water.

[0008] To achieve the above purpose, the technical solution of the present utility model is: a continuous production system for tetrabutylurea, stabilizer No. 1 and stabilizer No. 2, which is characterized in that it includes a main raw material vaporizer, a gas reactor, a condenser, a receiving tank and a reaction kettle;

[0009] A main raw material inlet pipeline and a gas outlet pipeline are arranged on the main raw material vaporizer. There is a phosgene inlet pipe and a main raw material gas inlet pipe at the top of the gas reactor. The main raw material gas inlet pipe is connected to the gas outlet pipeline of the main raw material vaporizer. There is a discharge port at the bottom of the gas reactor, which is connected to the condenser. The condenser is connected to the receiving tank. A hydrogen chloride discharge pipe is arranged on the receiving tank;

[0010] A sodium hydroxide solution adding pipeline, a main raw material adding pipeline and an intermediate state acyl chloride adding pipeline or a dropping funnel are arranged on the reaction kettle. The intermediate state acyl chloride adding pipeline or the dropping funnel is connected to the receiving tank.

[0011] In the above solution: it further includes a main raw material storage tank. The main raw material storage tank is connected to the main raw material vaporizer through the main raw material inlet pipeline. A metering pump and a valve are arranged on the main raw material inlet pipeline. By metering and adding main raw materials such as di-n-butylamine through the metering pump, automatic metering addition can be realized.

[0012] In the above solution: when the intermediate state acyl chloride adding pipeline is adopted, a flow control valve and a metering pump are arranged on the intermediate state acyl chloride adding pipeline.

[0013] In the above solution: a stirrer is arranged inside the reaction kettle, and a heating jacket is arranged outside it. A discharge pipe is arranged on the reaction kettle.

[0014] In the above solution: the sodium hydroxide solution adding pipeline is connected to a sodium hydroxide storage tank. A metering pump and a valve are arranged on the sodium hydroxide solution adding pipeline. By metering and adding the sodium hydroxide solution through the metering pump, automatic metering addition can be realized.

[0015] In the above solution, the main raw material adding pipeline of the reaction kettle is connected to the main raw material storage tank. A metering pump and a valve are arranged on the main raw material adding pipeline. By metering and adding di-n-butylamine through the metering pump, automatic metering addition can be realized.

[0016] The reaction steps are as follows: vaporize di-n-butylamine, then introduce it into the gas reactor together with excessive phosgene for reaction. After the reaction, condense it and discharge hydrogen chloride gas to obtain N, N-dibutylcarbamyl chloride;

[0017] Add sodium hydroxide solution and di-n-butylamine to the reaction vessel, stir, and dropwise add the N,N-dibutylcarbamyl chloride prepared in step (1), and heat the reaction to obtain the crude product of tetrabutylurea.

[0018] For tetrabutylurea, the main raw material refers to di-n-butylamine. For stabilizer No. I and stabilizer No. II, the main raw materials refer to N-ethylaniline and N-methylaniline respectively.

[0019] For tetrabutylurea, after vaporizing di-n-butylamine, it is converted into di-n-butylamine gas, and then it passes through a gas reactor together with phosgene. The gas reactor is filled with corrosion-resistant packing (such as ceramic packing. The gas reactor is a prior art and will not be elaborated here). Phosgene and di-n-butylamine react rapidly in the gas reactor to generate N,N-dibutylcarbamyl chloride and hydrogen chloride gas. The N,N-dibutylcarbamyl chloride (liquid) and hydrogen chloride gas are condensed in the condenser and then enter the receiving tank 4. A hydrogen chloride discharge pipeline is provided on the receiving tank 4. After hydrogen chloride and excess phosgene are discharged (vacuum suction can be supplemented to discharge the gas as much as possible), they are sent to the subsequent destruction system for treatment and recovery. In this step, an excess of phosgene is used to avoid the generation of solid dibutylamine hydrochloride, thus preventing the packing from being blocked. On the other hand, with an excess of phosgene, only N,N-dibutylcarbamyl chloride (liquid) is generated and tetrabutylurea will not be formed.

[0020] After the gas reaction is completed, add one more mole of di-n-butylamine and N,N-dibutylcarbamyl chloride to react in an environment of sodium hydroxide solution to generate tetrabutylurea. At this time, the amount of sodium hydroxide can be halved (because one molecule of hydrogen chloride has been discharged in the form of gas during the gas reaction, and only one molecule of hydrogen chloride needs to be neutralized by sodium hydroxide in this step reaction), thereby reducing the amount of alkaline wastewater by half and greatly reducing the amount of wastewater treatment.

[0021] The reactions of stabilizer No. I and stabilizer No. II are the same as that of tetrabutylurea, and the intermediate acyl chlorides are N-N-methyl-N-phenylcarbamyl chloride and ethyl-N-phenylcarbamyl chloride respectively. After the reactions of stabilizer No. I and stabilizer No. II are completed, stabilizer No. I is then cooled by adding water, stirred, and the product precipitates, and then filtered to remove the aqueous sodium chloride solution.

[0022] Stabilizer No. II is cooled by adding water, stirred, and the product precipitates, and then filtered to remove the aqueous sodium chloride solution. The crude product obtained by filtration is added to the distillation kettle for distillation to obtain the product.

[0023] The crude product of tetrabutylurea is allowed to stand, separated, distilled, and purified to obtain the final product of tetrabutylurea. This step is a prior art and can refer to the treatment method of CN 102702029 A.

[0024] Beneficial effects: Based on the prior art, the present utility model first undergoes a gas reaction, enabling one molecule of the main raw material to react with phosgene to form an intermediate state acyl chloride. At this time, the generated hydrogen chloride is in a gaseous state and is discharged and then destroyed and recycled in a gaseous form. There is no need to consume sodium hydroxide solution, reducing the generation of wastewater. Through this method, the yields of tetrabutylurea, stabilizer I, and stabilizer II are all greater than 95%, with high output and high purity. Moreover, the gas reaction is rapid, the reaction time of the second step is shortened by about one-third, and the overall efficiency is improved. Brief Description of the Drawings

[0025] Figure 1 is the process flow diagram of the present utility model. Detailed Embodiments

[0026] The present utility model will be further described below through embodiments in conjunction with the drawings:

[0027] Example 1, as Figure 1 shown, the reaction system includes a main raw material vaporizer 1, a gas reactor 2, a condenser 3, a receiving tank 4, a reaction kettle 5, and a main raw material storage tank 6.

[0028] The vaporizer is prior art. The condenser 3 can be a condenser tube or other condensation structures including a tube side and a shell side. The gas generated by the gas reactor passes through the tube side and is condensed by the condensate in the shell side. The gas reactor 2 is also prior art, and it is internally provided with fillers, and the fillers are acid and alkali resistant fillers such as ceramics. An external heating jacket is provided and steam can be introduced for heating.

[0029] The main raw material storage tank 6 is connected to the main raw material vaporizer 1 through a main raw material inlet pipeline. A metering pump 7 and a valve are provided on this main raw material inlet pipeline. The heating temperature of the main raw material vaporizer needs to ensure the vaporization of the main raw material. There is a phosgene inlet pipe and a main raw material gas inlet pipe at the top of the gas reactor 2. The main raw material gas inlet pipe is connected to the gas outlet pipeline of the main raw material vaporizer, and valves are provided on the phosgene inlet pipe and the main raw material gas inlet pipe. There is a discharge port at the bottom of the gas reactor 2 connected to the condenser 3, the condenser 3 is connected to the receiving tank 4, and a hydrogen chloride discharge pipe is provided on the receiving tank 4. The hydrogen chloride discharge pipe can be connected to a vacuum pipe to discharge hydrogen chloride as much as possible. Of course, a nitrogen pipeline can also be provided on the receiving tank 4 to blow out hydrogen chloride with nitrogen.

[0030] A sodium hydroxide solution addition pipeline, a main raw material addition pipeline, an intermediate state acyl chloride addition pipeline or a dropping funnel is provided on the reaction kettle 5. If an intermediate state acyl chloride addition pipeline is adopted, a flow control valve and a metering pump 7 can be provided on the intermediate state acyl chloride addition pipeline ( Figure 1The intermediate state acyl chloride is added into the pipeline) to control the addition speed of N, N-dibutylcarbamoyl chloride. Of course, a dropping funnel can also be used. When the production volume is small, a dropping funnel can be used. When the production volume is large, a flow control valve is directly used to control the addition speed. A stirring device is provided in the reactor 5, and a heating interlayer is provided outside the reactor 5. A discharge pipe is provided on the reactor 5. The sodium hydroxide solution addition pipeline is connected to the sodium hydroxide storage tank 8, and a metering pump and a valve are provided on the sodium hydroxide solution addition pipeline. The main raw material addition pipeline of the reactor is connected to the main raw material storage tank 6, and a metering pump and a valve are provided on the main raw material addition pipeline.

[0031] The present invention is not limited to the above embodiments. Those skilled in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and purpose of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A continuous production system of tetrabutylurea, No. I intermediate fixer and No. II intermediate fixer, characterized in that: It includes a main raw material vaporizer, a gas reactor, a condenser, a receiving tank and a reactor; The main raw material vaporizer is provided with a main raw material inlet pipeline and a gas outlet pipeline, a phosgene inlet pipe and a main raw material gas inlet pipe are provided at the top of the gas reactor, the main raw material gas inlet pipe is connected to the main raw material vaporizer gas outlet pipeline, a discharge port is provided at the bottom of the gas reactor and is connected to a condenser, the condenser is connected to a receiving tank, and a hydrogen chloride discharge pipe is provided on the receiving tank; The reactor is provided with a sodium hydroxide solution adding pipeline, a main raw material adding pipeline and an intermediate acyl chloride adding pipeline or a dropping funnel, and the intermediate acyl chloride adding pipeline or the dropping funnel is connected to a receiving tank.

2. The continuous production system of tetrabutylurea, No. I intermediate fixer and No. II intermediate fixer according to claim 1, characterized in that: It also includes a main raw material storage tank, which is connected to the main raw material vaporizer through a main raw material inlet pipeline, and a metering pump and a valve are arranged on the main raw material inlet pipeline.

3. The continuous production system of tetrabutylurea, No. I intermediate fixer and No. II intermediate fixer according to claim 1, characterized in that: When the intermediate acyl chloride adding pipeline is adopted, a flow control valve and a metering pump are arranged on the intermediate acyl chloride adding pipeline.

4. The continuous production system of tetrabutylurea, No. I intermediate fixer and No. II intermediate fixer according to claim 3, characterized in that: The reactor is provided with a stirring device inside, a heating interlayer outside, and a discharge pipe on the reactor.

5. The continuous production system of tetrabutylurea, No. I intermediate fixer and No. II intermediate fixer according to any one of claims 1 to 4, characterized in that: The sodium hydroxide solution adding pipeline is connected to the sodium hydroxide storage tank, and a metering pump and a valve are arranged on the sodium hydroxide solution adding pipeline.

6. The continuous production system of tetrabutylurea, No. I intermediate fixer and No. II intermediate fixer according to claim 5, characterized in that: The main raw material adding pipeline of the reactor is connected to the main raw material storage tank, and a metering pump and a valve are arranged on the main raw material adding pipeline.

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