CN105399652A - Preparation method of rubber vulcanization accelerator of dimethyldithiocarbamate selenium - Google Patents

Abstract

The invention discloses a method for preparing a rubber vulcanization accelerator selenium dimethyl dithiocarbamate, which comprises the following steps: (1) preparing a solution: preparing a selenium-containing solution; preparing a dimethyl dithiocarbamate solution; (2) Synthesis of selenium dimethyl dithiocarbamate: react the prepared selenium-containing solution with dimethyl dithiocarbamate solution, the reaction conditions are as follows: the pH value is 7-9, and the temperature is 0 -90°C; (3) separating selenium dimethyl dithiocarbamate to obtain the final product selenium dimethyl dithiocarbamate.

Description

A kind of preparation method of rubber vulcanization accelerator selenium dimethyl dithiocarbamate

technical field

The invention relates to the field of rubber vulcanization accelerators, in particular to a preparation method of a rubber vulcanization accelerator selenium dimethyl dithiocarbamate.

Background technique

Dithiocarbamate compounds are mainly used as super speed accelerators in the rubber vulcanization process. Compared with other types of vulcanization accelerators, dithiocarbamate accelerators have the advantages of fast vulcanization speed, low vulcanization temperature, good dispersion performance, high degree of crosslinking, and low toxicity, but they are easy to scorch and vulcanize flat Poor sex. The use of thiocarbamate accelerators can produce vulcanized rubber with higher tensile stress, but the tensile strength and elongation at break are lower than those of sulfenamide accelerators.

Studies have shown that when two ultra-fast vulcanization accelerators are used together, there will be a synergistic effect. The reason may be that the accelerators are easily miscible when used together, forming a salt-forming compound with greater solubility in rubber and greater chemical activity. At present, the vulcanization system in which two or more accelerators are used in combination is commonly used in the rubber processing industry. It has been reported in the literature that when xanthate/zinc diethyldithiocarbamate accelerator is used in combination with vulcanized natural rubber, it has a positive synergistic effect.

Selenium dimethyl dithiocarbamate is one of the thiocarbamates. Its main function is to combine with thiazoles for NR, IIR, and SBR. It does not change color in light-colored products, and is heat-resistant in low-sulfur products More effective in formulations, it can also be used as a vulcanizing agent.

At present, there is no literature or information to disclose the synthesis method of selenium dimethyl dithiocarbamate, and this gap needs to be filled.

Contents of the invention

For above-mentioned defect, the technical problem that the present invention solves is to provide a kind of preparation method of rubber vulcanization accelerator selenium dimethyl dithiocarbamate.

In order to solve the above technical problems, the preparation method of rubber vulcanization accelerator dimethyl dithiocarbamate selenium provided by the invention comprises the steps:

(1) Prepare the solution

Preparation of selenium-containing solution: dissolving selenium oxide with lye or water to form a selenium-containing solution; or dissolving selenite in water to obtain a selenium-containing solution;

Prepare dimethyl dithiocarbamate solution: dissolve dimethyl dithiocarbamate in water to form dimethyl dithiocarbamate solution;

(2) Synthesis of selenium dimethyl dithiocarbamate

The configured selenium-containing solution is reacted with the dimethyl dithiocarbamate solution, and the reaction conditions are as follows:

The pH value is 7-9, and the temperature is 0-90°C;

(3) Separation of selenium dimethyl dithiocarbamate.

Preferably, in step (1), the concentration of selenium in the selenium-containing solution is 0.25-1mol/L.

3 Preferably, in step (1), the concentration of the lye is 1-3 times that of the selenium-containing solution.

Preferably, in step (1), the lye reacts with selenium oxide to generate corresponding selenite.

Preferably, in step (1), the lye is prepared from one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate or potassium bicarbonate.

Preferably, in step (1), the concentration of the dimethyl dithiocarbamate solution is 10-40 wt%.

Preferably, in step (2), the pH value of the reaction condition is adjusted to 7-9 with an acid solution, and the acid solution is prepared by one or more of hydrochloric acid, acetic acid or nitric acid.

Preferably, the acid solution has a concentration of 0.5-2 mol/L.

Preferably, in step (2), the configured selenium-containing solution is reacted with the dimethyl dithiocarbamate solution, and the pH value at the end of the reaction is 6-7.

Preferably, in step (3), selenium dimethyl dithiocarbamate is separated:

The selenium dimethyl dithiocarbamate product is processed by conventional methods of filtering, washing, drying and crushing to obtain the final product selenium dimethyl dithiocarbamate.

Compared with prior art, the preparation method of rubber vulcanization accelerator dimethyl dithiocarbamate selenium of the present invention has the following advantages:

1. No waste gas and waste residue are produced during the production process of the product, which has little environmental pollution;

2. The product has high purity, which can reach more than 99%;

3. High yield, up to 95%.

Description of drawings

Fig. 1 is the flowchart of the preparation method of rubber vulcanization accelerator selenium dimethyl dithiocarbamate in the embodiment of the present invention, wherein, SeDMC is selenium dimethyl dithiocarbamate.

detailed description

In order for those skilled in the art to better understand the technical solutions provided by the present invention, the following will be described in conjunction with specific embodiments.

Please refer to FIG. 1 , which is a flow chart of the preparation method of the rubber vulcanization accelerator selenium dimethyl dithiocarbamate in the embodiment of the present invention, wherein SeDMC is selenium dimethyl dithiocarbamate.

The present invention comprises the following steps:

(1) Prepare the solution

Preparation of selenium-containing solution: dissolving selenium oxide with lye or water to form a selenium-containing solution; or dissolving selenite in water to obtain a selenium-containing solution;

Prepare dimethyl dithiocarbamate solution: dissolve dimethyl dithiocarbamate in water to form dimethyl dithiocarbamate solution;

(2) Synthesis of selenium dimethyl dithiocarbamate

The configured selenium-containing solution is reacted with the dimethyl dithiocarbamate solution, and the reaction conditions are as follows:

The pH value is 7-9, and the temperature is 0-90°C;

Adjust the pH value of the reaction conditions with an acid solution;

(3) Separation of selenium dimethyl dithiocarbamate

The selenium dimethyl dithiocarbamate product is processed by conventional methods of filtering, washing, drying and crushing to obtain the final product selenium dimethyl dithiocarbamate.

Example 1

The preparation method of the rubber vulcanization accelerator selenium dimethyl dithiocarbamate provided in the embodiment of the present invention is to dissolve 62.5 g of dimethyl dithiocarbamate in 94 g of water, raise the temperature to 80 ° C, and wait for complete After dissolving, add 100ml of 0.5mol/L selenous acid into the reaction system, and after stirring for 30min, slowly add 1mol/L hydrochloric acid into the reaction system with stirring within 1h until the pH value of the system is between 6-7. The pale yellow precipitate that appears during the pH adjustment is selenium dimethyldithiocarbamate. The product was washed and filtered, and dried at 90°C to obtain 26.7g of selenium dimethyl dithiocarbamate product, wherein the selenium content was 14.5%, and the melting point was 256-265°C.

Example 2

The preparation method of the rubber vulcanization accelerator selenium dimethyl dithiocarbamate that the embodiment of the present invention provides, the dimethyl dithiocarbamate of 62.5g is dissolved in the water of 146g, controls reaction temperature 5 with ice-water bath -10°C, after completely dissolving, add 100ml of 0.5mol/L selenous acid into the reaction system, stir for 30min, then slowly add 1mol/L hydrochloric acid into the reaction system under stirring within 1h until the pH value of the system reaches 6 Between -7. The pale yellow precipitate that appears during the pH adjustment is selenium dimethyldithiocarbamate. The product was washed and filtered, and dried at 90°C to obtain 27.3g of selenium dimethyl dithiocarbamate product, wherein the selenium content was 14.3%, and the melting point was 249-262°C.

Example 3

The preparation method of the rubber vulcanization accelerator selenium dimethyl dithiocarbamate that the embodiment of the present invention provides, the dimethyl dithiocarbamate of 62.5g is dissolved in the water of 146g, controls reaction temperature 5 with ice-water bath -10°C, after completely dissolving, add 100ml of 0.5mol/L selenous acid into the reaction system, after stirring for 30min, slowly add 1mol/L hydrochloric acid into the reaction system under stirring condition within 1h until the pH value of the system reaches 6 Between -7. The pale yellow precipitate that appears during the pH adjustment is selenium dimethyl dithiocarbamate. The product was washed and filtered, and dried at 90°C to obtain 27.3g of selenium dimethyl dithiocarbamate product, wherein the selenium content was 14.3%, and the melting point was 249-262°C.

Example 4

The preparation method of the rubber vulcanization accelerator dimethyl dithiocarbamate selenium that the embodiment of the present invention provides, the dimethyl dithiocarbamate of 62.5g is dissolved in the sodium hydroxide lye of 178g, with ice Control the reaction temperature in a water bath at 30-60°C. After completely dissolving, add 100ml of 0.75mol/L sodium selenite into the reaction system, stir for 30min, then slowly add 1mol/L of nitric acid into the reaction system within 1h under stirring until the pH value of the system is between 6-7. The pale yellow precipitate that appears during the pH adjustment is selenium dimethyl dithiocarbamate. The product was washed and filtered, and dried at 90°C to obtain 26.3g of selenium dimethyl dithiocarbamate product, wherein the selenium content was 13.8%, and the melting point was 242-261°C.

Compared with prior art, the preparation method of rubber vulcanization accelerator dimethyl dithiocarbamate selenium of the present invention has the following advantages:

1. No waste gas and waste residue are produced during the production process of the product, which has little environmental pollution;

2. The purity of the product is high, up to 99% or more;

3. High yield, up to 95%.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. a preparation method for thiofide Selenium dimethyl dithiocarbamate, is characterized in that, comprises the steps:

(1) obtain solution

Preparation Se solution: by selenium oxide alkali lye or water dissolution, forms the solution containing selenium; Or by selenite water dissolution, obtain the solution containing selenium;

Preparation dimethyl dithiocarbamate solution: dimethyl dithiocarbamate is soluble in water, forms dimethyl dithiocarbamate solution;

(2) synthesization of dimethyl disulfide is for carboxylamine selenium

The Se solution configured and dimethyl dithiocarbamate solution are reacted, reaction conditions is as follows:

PH value is 7-9, and temperature is 0-90 DEG C;

(3) Selenium dimethyl dithiocarbamate is separated.

2. the preparation method of thiofide Selenium dimethyl dithiocarbamate according to claim 1, is characterized in that, in step (1), in Se solution, the concentration of selenium is 0.25-1mol/L.

3. the preparation method of thiofide Selenium dimethyl dithiocarbamate according to claim 2, is characterized in that, in step (1), the concentration of alkali lye is concentration 1-3 times of Se solution.

4. the preparation method of thiofide Selenium dimethyl dithiocarbamate according to claim 3, is characterized in that, in step (1), alkali lye reacts to selenium oxide and generates corresponding selenite.

5. the preparation method of thiofide Selenium dimethyl dithiocarbamate according to claim 3, it is characterized in that, in step (1), alkali lye is formulated by one or more materials in sodium hydroxide, potassium hydroxide, sodium carbonate, salt of wormwood, sodium bicarbonate or saleratus.

6. the preparation method of thiofide Selenium dimethyl dithiocarbamate according to claim 1, is characterized in that, in step (1), the concentration of dimethyl dithiocarbamate solution is 10-40wt%.

7. the preparation method of thiofide Selenium dimethyl dithiocarbamate according to claim 1, it is characterized in that, in step (2), regulate reaction conditions pH value to be 7-9 with acid solution, acid solution is formulated by one or more of hydrochloric acid, acetic acid or nitric acid.

8. the preparation method of thiofide Selenium dimethyl dithiocarbamate according to claim 7, is characterized in that, the concentration of acid solution is 0.5-2mol/L.

9. the preparation method of thiofide Selenium dimethyl dithiocarbamate according to claim 1, it is characterized in that, in step (2), the Se solution configured and dimethyl dithiocarbamate solution are reacted, the endpoint pH of reaction is at 6-7.

10. the preparation method of thiofide Selenium dimethyl dithiocarbamate according to claim 1, is characterized in that, in step (3), is separated Selenium dimethyl dithiocarbamate:

Conventional filtration, washing, drying, breaking method is adopted to process Selenium dimethyl dithiocarbamate product, thus obtain the finished product Selenium dimethyl dithiocarbamate.