CN105367468A - Preparation method of rubber vulcanization accelerator selenium dimethyldithiocarbamate - Google Patents

Abstract

The invention discloses a method for preparing a rubber vulcanization accelerator selenium dimethyl dithiocarbamate, which comprises the following steps: sequentially adding specified amounts of dimethylamine solution, selenous acid solution and nonionic surfactant in a stirring state To pure water, control the temperature at 0-40°C, then start to drop a specified amount of carbon disulfide liquid, control the reaction time of 1-4 hours, after the dropwise addition, raise the temperature to 30-40°C, stir for 0.5-2 hours, After the reaction, use an acid solution to adjust the pH value of the reaction solution to 6-7, and then stir for 0.5-2 hours, then carry out solid-liquid separation, and use conventional solid drying, crushing, and sieving methods to remove the dimethyldithioamino The selenium formate product is processed to obtain the final product, selenium dimethyldithiocarbamate.

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:

Add specified amount of dimethylamine solution, selenous acid solution and non-ionic surfactant to pure water sequentially under stirring state, control the temperature at 0-40°C, then start to drop specified amount of carbon disulfide liquid, control 1- The reaction time is 4 hours. After the dropwise addition is completed, the temperature is raised to 30-40°C and stirred for 0.5-2 hours. Solid-liquid separation, using conventional solid drying, crushing, and sieving methods to process the selenium dimethyl dithiocarbamate product, so as to obtain the final product selenium dimethyl dithiocarbamate; wherein:

The stoichiometric molar ratio of dimethylamine, carbon disulfide, selenous acid and nonionic surfactant is 1:0.8-1.2:0.2-0.25:0.01-0.025mol.

Preferably, the concentration of the dimethylamine solution is: 10-40wt%.

Preferably, the concentration of the selenous acid solution is: 0.25-1mol/L.

Preferably, the acid solution is prepared from one or more of hydrochloric acid, acetic acid or nitric acid.

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

In addition, the present invention provides a method for preparing rubber vulcanization accelerator selenium dimethyl dithiocarbamate, comprising the steps of:

Add the specified amount of dimethylamine solution, sodium selenite solution and non-ionic surfactant to pure water in a stirring state, control the temperature at 0-40°C, then start to drop the specified amount of carbon disulfide liquid, control 1 The reaction time is -4 hours. After the dropwise addition is completed, the temperature is raised to 30-40° C. and stirred for 0.5-2 hours. After the reaction is completed, the pH value of the reaction solution is adjusted to 6-7 with an acid solution, and then stirred for 0.5-2 hours. Solid-liquid separation is carried out, and the selenium dimethyl dithiocarbamate product is processed by conventional solid drying, crushing and sieving methods, so as to obtain the final product selenium dimethyl dithiocarbamate; wherein:

The stoichiometric molar ratio of dimethylamine, carbon disulfide, sodium selenite and nonionic surfactant is 1:0.8-1.2:0.2-0.25:0.01-0.025mol.

Preferably, the concentration of the dimethylamine solution is: 10-40wt%.

Preferably, the concentration of the sodium selenite solution is: 0.25-1mol/L.

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

1. The present invention does not discharge salty waste water during the production process, and has little environmental pollution;

2, the method of the present invention has reduced the production link of intermediate semi-finished product, and production cycle is short, has reduced production cost;

3. The initial melting point of the selenium dimethyl dithiocarbamate product is ≥ 250°C, and the purity is ≥ 99%.

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.

Example 1

The preparation method of the rubber vulcanization accelerator dimethyl dithiocarbamate selenium provided by the embodiment of the present invention, the raw materials used and the stoichiometric molar ratio thereof are dimethylamine: carbon disulfide: selenous acid: nonionic surfactant=1: 0.9:0.2:0.01. The process is as follows: add dimethylamine solution, non-ionic surfactant, and selenous acid solution to the reaction kettle filled with pure water in a stirring state, and add carbon disulfide liquid dropwise after stirring for 30 minutes. The dropping time is 2 hours. The temperature is controlled at 25°C, and then the temperature is raised to 40°C to continue stirring and reacting for 1 hour, and the solid-liquid separation is carried out, and the solid is dried, pulverized, and packaged. The concentration of the dimethylamine solution is: 30wt%. The concentration of selenous acid solution is: 0.8mol/L.

The yield of the obtained product is 96.5%, the initial melting point is 252--260° C., and the selenium content is 14.6%.

Example 2

The preparation method of the rubber vulcanization accelerator dimethyl dithiocarbamate selenium provided by the embodiment of the present invention, the raw materials used and the stoichiometric molar ratio thereof are dimethylamine: carbon disulfide: selenous acid: nonionic surfactant=1: 1.1:0.25:0.015. The process is as follows: add dimethylamine solution, non-ionic surfactant, and selenous acid solution to the reaction kettle filled with pure water in a stirring state, and then add carbon disulfide liquid dropwise after stirring for 50 minutes. The dropping time is 3 hours. The temperature is controlled at 25°C, and then the temperature is raised to 40°C to continue stirring and reacting for 1 hour, and the solid-liquid separation is carried out, and the solid is dried, pulverized, and packaged. The concentration of the dimethylamine solution is: 20wt%. The concentration of selenous acid solution is: 0.5mol/L.

The yield of the obtained product is 95.8%, the initial melting point is 250--260°C, and the selenium content is 14.6%.

Example 3

The preparation method of the rubber vulcanization accelerator dimethyl dithiocarbamate selenium provided by the embodiment of the present invention, the raw materials used and the stoichiometric molar ratio thereof are dimethylamine: carbon disulfide: selenous acid: nonionic surfactant=1: 1.2:0.25:0.015. The process is as follows: add dimethylamine solution, non-ionic surfactant, and selenous acid solution to the reaction kettle filled with pure water in a stirring state, and then add carbon disulfide liquid dropwise after stirring for 30 minutes. The dropping time is 4 hours. The temperature was controlled at 8°C. Afterwards, the temperature was raised to 40° C. and the stirring reaction was continued for 1 hour, the solid-liquid separation was carried out, the liquid was discarded, and the solid was dried, pulverized, and packaged. The concentration of the dimethylamine solution is: 40wt%. The concentration of selenous acid solution is: 1mol/L.

The yield of the obtained product is 97.2%, the initial melting point is 255--262°C, and the selenium content is 14.3%.

Example 4

The preparation method of the rubber vulcanization accelerator selenium dimethyl dithiocarbamate provided by the embodiment of the present invention, the raw materials used and the stoichiometric molar ratio thereof are dimethylamine: carbon disulfide: sodium selenite: nonionic surfactant=1 :0.9:0.2:0.01. The process is as follows: add dimethylamine solution, non-ionic surfactant, and sodium selenite solution to the reaction kettle filled with pure water in a stirring state, and add carbon disulfide liquid dropwise after stirring for 30 minutes. The dropping time is 2 hours. , the temperature is controlled at 25°C, and then the temperature is raised to 40°C to continue stirring and reacting for 1 hour, and solid-liquid separation is carried out, and the solid is dried, pulverized, and packaged. The concentration of the dimethylamine solution is: 30wt%. The concentration of sodium selenite solution is: 0.8mol/L.

The yield of the obtained product is 96.5%, the initial melting point is 252--260° C., and the selenium content is 14.6%.

Example 5

The preparation method of the rubber vulcanization accelerator selenium dimethyl dithiocarbamate provided by the embodiment of the present invention, the raw materials used and the stoichiometric molar ratio thereof are dimethylamine: carbon disulfide: sodium selenite: nonionic surfactant=1 :1.1:0.25:0.015. The process is as follows: add dimethylamine solution, non-ionic surfactant, and sodium selenite solution to the reaction kettle filled with pure water in a stirring state, and add carbon disulfide liquid dropwise after stirring for 50 minutes. The dropping time is 3 hours. , the temperature is controlled at 25°C, and then the temperature is raised to 40°C to continue stirring and reacting for 1 hour, and solid-liquid separation is carried out, and the solid is dried, pulverized, and packaged. The concentration of the dimethylamine solution is: 20wt%. The concentration of sodium selenite solution is: 0.5mol/L.

The yield of the obtained product is 95.8%, the initial melting point is 250--260°C, and the selenium content is 14.6%.

Example 6

The preparation method of the rubber vulcanization accelerator selenium dimethyl dithiocarbamate provided by the embodiment of the present invention, the raw materials used and the stoichiometric molar ratio thereof are dimethylamine: carbon disulfide: sodium selenite: nonionic surfactant=1 :1.2:0.25:0.015. The process is as follows: add dimethylamine solution, non-ionic surfactant, and sodium selenite solution to the reaction kettle filled with pure water in a stirring state, and add carbon disulfide liquid dropwise after stirring for 30 minutes. The dropping time is 4 hours. , the temperature was controlled at 8°C. Afterwards, the temperature was raised to 40° C. and the stirring reaction was continued for 1 hour, the solid-liquid separation was carried out, the liquid was discarded, and the solid was dried, pulverized, and packaged. The concentration of the dimethylamine solution is: 40wt%. The concentration of sodium selenite solution is: 1mol/L.

The yield of the obtained product is 97.2%, the initial melting point is 255--262°C, and the selenium content is 14.3%.

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

1. The present invention does not discharge salty waste water during the production process, and has little environmental pollution;

2, the method of the present invention has reduced the production link of intermediate semi-finished product, and production cycle is short, has reduced production cost;

3. The initial melting point of the selenium dimethyl dithiocarbamate product is ≥ 250°C, and the purity is ≥ 99%.

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 (8)

1. a preparation method of rubber vulcanization accelerator dimethyl dithiocarbamate selenium, is characterized in that, comprises the steps: Add specified amount of dimethylamine solution, selenous acid solution and non-ionic surfactant to pure water sequentially under stirring state, control the temperature at 0-40°C, then start to drop specified amount of carbon disulfide liquid, control 1- The reaction time is 4 hours. After the dropwise addition is completed, the temperature is raised to 30-40°C and stirred for 0.5-2 hours. Solid-liquid separation, using conventional solid drying, crushing, and sieving methods to process the selenium dimethyl dithiocarbamate product, so as to obtain the final product selenium dimethyl dithiocarbamate; wherein: The stoichiometric molar ratio of dimethylamine, carbon disulfide, selenous acid and nonionic surfactant is 1:0.8-1.2:0.2-0.25:0.01-0.025mol. 2. the preparation method of rubber vulcanization accelerator dimethyl dithiocarbamate selenium according to claim 1, is characterized in that, the concentration of described dimethylamine solution is: 10-40wt%. 3. the preparation method of rubber vulcanization accelerator dimethyl dithiocarbamate selenium according to claim 2, is characterized in that, the concentration of described selenous acid solution is: 0.25-1mol/L. 4. the preparation method of rubber vulcanization accelerator dimethyl dithiocarbamate selenium according to claim 1, is characterized in that, described acid solution is formulated by one or more of hydrochloric acid, acetic acid or nitric acid . 5. the preparation method of rubber vulcanization accelerator dimethyl dithiocarbamate selenium according to claim 4, is characterized in that, the concentration of described acid solution is 0.5-2mol/L. 6. a preparation method of rubber vulcanization accelerator dimethyl dithiocarbamate selenium, is characterized in that, comprises the steps: Add the specified amount of dimethylamine solution, sodium selenite solution and non-ionic surfactant to pure water in a stirring state, control the temperature at 0-40°C, then start to drop the specified amount of carbon disulfide liquid, control 1 The reaction time is -4 hours. After the dropwise addition is completed, the temperature is raised to 30-40° C. and stirred for 0.5-2 hours. After the reaction is completed, the pH value of the reaction solution is adjusted to 6-7 with an acid solution, and then stirred for 0.5-2 hours. Solid-liquid separation is carried out, and the selenium dimethyl dithiocarbamate product is processed by conventional solid drying, crushing, and sieving methods, so as to obtain the final product selenium dimethyl dithiocarbamate; wherein: The stoichiometric molar ratio of dimethylamine, carbon disulfide, sodium selenite and nonionic surfactant is 1:0.8-1.2:0.2-0.25:0.01-0.025mol. 7. The preparation method of the rubber vulcanization accelerator selenium dimethyl dithiocarbamate according to claim 6, characterized in that, the concentration of the dimethylamine solution is: 10-40wt%. 8. The preparation method of the rubber vulcanization accelerator selenium dimethyl dithiocarbamate according to claim 6, characterized in that, the concentration of the sodium selenite solution is: 0.25-1mol/L.