CN114853646A

CN114853646A - Method for synthesizing dimethyl dithiodipropionate based on continuous vulcanization reaction

Info

Publication number: CN114853646A
Application number: CN202210689064.1A
Authority: CN
Inventors: 王艳红; 孙仿建; 董学建; 王泽东; 袁令华
Original assignee: Shandong Yubin New Material Co ltd
Current assignee: Shandong Yubin New Material Co ltd
Priority date: 2022-06-17
Filing date: 2022-06-17
Publication date: 2022-08-05

Abstract

The invention discloses a method for synthesizing dimethyl dithiodipropionate based on continuous vulcanization reaction, which comprises the following steps: adding ammonia water into methyl acrylate, stirring and mixing, adding sulfur powder, and stirring until the solid is dissolved to prepare a mixed solution; introducing the mixed solution and hydrogen sulfide gas from the upper part and the lower part of the tubular reactor respectively to carry out continuous vulcanization reaction; after the reaction is finished, the feed liquid collected from the bottom of the tubular reactor is subjected to standing layering treatment, an organic layer is collected, namely the target product dimethyl dithiodipropionate, and a water layer is recycled. The method provided by the invention is simple to operate, low in cost, high in product yield and purity, and suitable for industrial production.

Description

Method for synthesizing dimethyl dithiodipropionate based on continuous vulcanization reaction

Technical Field

The invention relates to the technical field of organic synthesis, in particular to a method for synthesizing dimethyl dithiodipropionate based on continuous vulcanization reaction.

Background

Dimethyl dithiodipropionate is an important chemical raw material and is widely applied to the aspects of medical intermediates, bactericides, cosmetics and the like. At present, the preparation method of the dimethyl dithiodipropionate comprises the following two methods:

(1) sodium hydrosulfide, hydrochloric acid, sulfur powder and methyl acrylate are used as raw materials to prepare the dimethyl dithiodipropionate. The method has the defects of low yield, more impurities, long reaction time, generation of a large amount of wastewater in the production process, need of later-stage triple-effect evaporation treatment to become hazardous waste, extremely high cost and high treatment cost.

(2) Hydrogen sulfide, ammonia water, excessive sulfur powder (excessive 30 percent) and methyl acrylate are used as raw materials to prepare the dimethyl dithiodipropionate. The method has the defects that after the reaction is finished, sodium sulfite is added at high temperature for refining, excessive sulfur powder is removed by reaction, and a byproduct is sodium thiosulfate. The sodium thiosulfate has few purposes, high impurities and high subsequent treatment cost. Is not beneficial to the reasonable utilization of resources. From the above, how to provide a method with high yield, high purity, low preparation cost and simple process to prepare the dimethyl dithiodipropionate has important research significance.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: aiming at the defects in the prior art, the method for synthesizing the dimethyl dithiodipropionate based on the continuous vulcanization reaction is provided, the method is suitable for a tubular reactor, the process is simple, the cost is low, the prepared product has high yield and high purity, no by-product is generated, and the method is suitable for industrial production.

In order to solve the technical problems, the technical scheme of the invention is as follows:

a method for synthesizing dimethyl dithiodipropionate based on continuous vulcanization reaction comprises the following steps:

(1) adding ammonia water into methyl acrylate, stirring and mixing, adding sulfur powder, and stirring until the solid is dissolved to obtain a mixed solution;

(2) introducing the mixed solution and hydrogen sulfide gas from the upper part and the lower part of the tubular reactor respectively to carry out continuous vulcanization reaction;

(3) and (3) after the reaction is finished, carrying out standing layering treatment on the feed liquid collected from the bottom of the tubular reactor, collecting an organic layer, namely the target product dimethyl dithiodipropionate, and repeatedly using the water layer in the step (1).

Preferably, in the step (1), the mass concentration of the ammonia water is 20 to 25 wt%.

Preferably, in the step (1), the mass ratio of the methyl acrylate to the sulfur powder to the ammonia water is 43 (8-8.1): 1.

preferably, in the step (2), the introduction speed of the hydrogen sulfide gas is 850-.

Preferably, in the step (2), the time from the top of the tubular reactor to the bottom of the tubular reactor is 1-1.2 min.

Preferably, in the step (2), the flow rate of the mixed solution is 5200-5210 kg/h.

Preferably, in the step (2), the temperature of the continuous vulcanization reaction is 20 ℃ to 50 ℃.

Due to the adoption of the technical scheme, the invention has the beneficial effects that:

(1) the method provided by the invention has the advantages that the sulfur powder and the methyl acrylate are fully stirred, so that the sulfur powder is uniformly dispersed in the methyl acrylate, the reaction materials fully participate in the reaction, the problem of excessive hydrogen sulfide or excessive sulfur powder cannot exist in the reaction process, and the purity of the product dimethyl dithiodipropionate is improved.

(2) The tubular reactor is adopted for continuous vulcanization reaction, the tubular reactor is thin, the cooling is uniform, the heat exchange efficiency is high, the reaction materials can fully participate in the reaction at a high feeding speed, and the feeding speed of the reaction materials when the tubular reactor is adopted is 10-12 times of that when the original reaction kettle is adopted as the reactor, so that the reaction time is greatly reduced, and the productivity is improved. In addition, the tubular reactor is adopted for reaction, so that the continuous production of products can be realized, and the productivity is further improved.

(3) According to the invention, the sulfur powder, the ammonia water and the methyl acrylate are mixed and then are respectively and simultaneously introduced into the tubular reactor with the hydrogen sulfide gas, so that the sulfur powder and the hydrogen sulfide gas are ensured to be added separately, the problem of hydrogen sulfide gas escape when the sulfur powder is added is avoided, and the environmental protection and safety of production are ensured.

(4) The invention effectively adjusts the introduction speed of the mixed liquid of the sulfur powder, the ammonia water and the methyl acrylate and the hydrogen sulfide gas, so that all reaction materials are in full contact reaction, thereby ensuring the purity of the target product, and after the reaction is finished and the mixture is kept stand for layering, the refining is not needed, the material loss is reduced, the production cost of the product is reduced, and the yield of the product is improved.

Description of the drawings:

FIG. 1 is a chromatogram of a dimethyl dithiodipropionate standard;

FIG. 2 is a chromatogram of a sample of dimethyl dithiodipropionate prepared in example 1;

FIG. 3 is a chromatogram of a sample of dimethyl dithiodipropionate prepared in example 2.

Detailed Description

The invention is further illustrated by the following examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

Example 1

(1) adding acrylic ester and ammonia water with the mass concentration of 20 wt% into a stirring kettle according to the mass ratio of 43:1, uniformly stirring and mixing, then adding sulfur powder accounting for 18.6% of the mass of methyl acrylate, and continuously stirring until the solid is dissolved to obtain a mixed solution;

(2) controlling the temperature inside the tubular reactor to be 30 ℃, introducing the mixed liquid prepared in the step (1) from the upper part of the tubular reactor at the introduction speed of 5200kg/h, simultaneously introducing hydrogen sulfide gas from the bottom of the tubular reactor at the introduction speed of 850kg/h, carrying out continuous vulcanization reaction, and collecting feed liquid from the bottom of the tubular reactor;

(3) and (3) carrying out standing layering treatment on the feed liquid collected at the bottom of the tubular reactor, wherein an organic layer collected after layering is dimethyl dithiodipropionate, and a water layer collected after layering is reused in the step (1).

The chromatograms of the dimethyldithiodipropionate standard sample and the target product prepared in this example are shown in fig. 1 and fig. 2, respectively. As can be seen from FIGS. 1 and 2, the peaks in the chromatograms at around 5.6 to 5.7 minutes are the peak shapes of dimethyl dithiodipropionate. FIG. 1 shows a standard sample, with a dimethyl dithiodipropionate content of 99.7%. As can be seen from fig. 2, the content of dimethyl dithiodipropionate produced in this example is 99.67%, and the other three impurity peaks in fig. 2 are respectively as follows in the order of appearance: methyl acrylate, methyl 3-mercaptopropionate, dimethyl thiodipropionate.

Example 2

(1) adding acrylic ester and ammonia water with the mass concentration of 20 wt% into a stirring kettle according to the mass ratio of 43:1, uniformly stirring and mixing, then adding sulfur powder accounting for 18.8% of the mass of methyl acrylate, and continuously stirring until the solid is dissolved to obtain a mixed solution;

(2) controlling the temperature inside the tubular reactor to be 40 ℃, introducing the mixed liquid prepared in the step (1) from the upper part of the tubular reactor at the introduction speed of 5205kg/h, simultaneously introducing hydrogen sulfide gas from the bottom of the tubular reactor at the introduction speed of 860kg/h, carrying out continuous vulcanization reaction, and collecting feed liquid from the bottom of the tubular reactor;

The chromatogram of the product prepared in this example is shown in fig. 3, and it can be seen from fig. 3 that an additional impurity peak appears after the dimethyl dithiodipropionate due to the increased addition ratio of sulfur powder, the material name of the peak is dimethyl trithiodipropionate, but the content of the peak is very low, which does not affect the subsequent reaction, and it can be seen from fig. 3 that the content of the target product dimethyl dithiodipropionate in this example is 99.55%, and the purity is very high.

Example 3

(1) adding acrylic ester and ammonia water with the mass concentration of 20 wt% into a stirring kettle according to the mass ratio of 43:1, uniformly stirring and mixing, then adding sulfur powder accounting for 18.7% of the mass of methyl acrylate, and continuously stirring until the solid is dissolved to obtain a mixed solution;

(2) controlling the temperature inside the tubular reactor to be 30 ℃, introducing the mixed liquid prepared in the step (1) from the upper part of the tubular reactor at the introduction speed of 5207kg/h, simultaneously introducing hydrogen sulfide gas from the bottom of the tubular reactor at the introduction speed of 865kg/h, carrying out continuous vulcanization reaction, and collecting feed liquid from the bottom of the tubular reactor;

Example 4

(1) adding acrylic ester and 25 wt% ammonia water into a stirring kettle according to the mass ratio of 43:1, uniformly stirring and mixing, then adding sulfur powder accounting for 18.6% of the mass of methyl acrylate, and continuously stirring until the solid is dissolved to obtain a mixed solution;

(2) controlling the temperature inside the tubular reactor to be 40 ℃, introducing the mixed liquid prepared in the step (1) from the upper part of the tubular reactor at the introduction speed of 5208kg/h, simultaneously introducing hydrogen sulfide gas from the bottom of the tubular reactor at the introduction speed of 870kg/h, carrying out continuous vulcanization reaction, and collecting feed liquid from the bottom of the tubular reactor;

The yields and purities of the products obtained in the above examples are shown in table 1.

TABLE 1

	Yield and content of	Purity%
			Example 1	98.5	99.67
Example 2	98.8	99.55
			Example 3	98.8	99.72
Example 4	98.6	99.61

As can be seen from the test data in Table 1, the yield of the product prepared by the method provided by the invention is more than 98%, and the purity is more than 99%.

Further, it should be understood that various changes or modifications of the present invention can be made by those skilled in the art after reading the teaching of the present invention, and these equivalents also fall within the scope of the claims appended to the present application.

Claims

1. A method for synthesizing dimethyl dithiodipropionate based on continuous vulcanization reaction is characterized by comprising the following steps:

(1) adding ammonia water into methyl acrylate, stirring and mixing, adding sulfur powder, and stirring until the solid is dissolved to prepare a mixed solution;

2. The method for synthesizing dimethyl dithiodipropionate according to claim 1, wherein the mass concentration of the ammonia water in step (1) is 20-25 wt%.

3. The method for synthesizing the dimethyl dithiodipropionate based on the continuous vulcanization reaction according to claim 1, wherein in the step (1), the mass ratio of the methyl acrylate to the sulfur powder to the ammonia water is 43 (8-8.1): 1.

4. the method for synthesizing dimethyl dithiodipropionate based on continuous vulcanization according to claim 1, wherein in the step (2), the introduction rate of the hydrogen sulfide gas is 850-870 kg/h.

5. The method for synthesizing the dimethyl dithiodipropionate based on continuous vulcanization reaction according to claim 1, wherein in the step (2), the time from the liquid inlet of the tubular reactor from the top to the liquid outlet of the reaction material at the bottom is 1-1.2 min.

6. The method for synthesizing dimethyl dithiodipropionate according to claim 1, wherein in step (2), the mixed solution is introduced at a rate of 5200-5210 kg/h.

7. The method for synthesizing the dimethyl dithiodipropionate based on continuous vulcanization reaction according to claim 1, wherein the temperature of the continuous vulcanization reaction in step (2) is 20 ℃ to 50 ℃.