Rubber vulcanization accelerator NS purification reaction filtration and washing integrated machine

 Rubber vulcanization accelerator NS, also known as TBBS, has the chemical name N-tert-butyl-2-benzothiazole sulfenamide. It is one of the important varieties of sulfenamide accelerators, featuring anti-scorching, non-toxicity, fast vulcanization and good aftereffect. It is mainly used in natural rubber, butadiene rubber, styrene-butadiene rubber and isoprene rubber.

There are many methods for the synthesis and purification of rubber vulcanization accelerator NS. Currently, the traditional methods for synthesizing NS all adopt the sodium hypochlorite oxidation method. The sodium hypochlorite oxidation method has a mature process, simple equipment and is easy to operate. However, the recovery of tert-butylamine is difficult during the synthesis and purification process, and a large amount of salt-containing wastewater is produced, causing environmental pollution. Among various oxidants, hydrogen peroxide has the advantage of being environmentally friendly and green. However, hydrogen peroxide has poor selective oxidizing properties in the later stage of NS synthesis, resulting in a relatively low yield.

In view of the deficiencies of the existing technology, the synthesis and purification method of the new rubber vulcanization accelerator NS, using hydrogen peroxide as the oxidant, through the catalyst and the combined process of cylindrical and conical filtration and washing, has improved the product quality and yield. Moreover, the process operation is simple and environmentally friendly. Compared with the existing technology, the advantages of the new process lie in:

(1) The new process uses hydrogen peroxide as the oxidant, featuring simple operation, significantly enhanced safety during production, and the generation of a large amount of high-salt wastewater. The production wastewater is easy to treat and reusable, achieving zero discharge of wastewater, which is conducive to cost savings and environmental protection.

(2) The new process selects iron tetrasulfonyl phthalocyanine as the catalyst to catalyze the decomposition of hydrogen peroxide. In the combination of cylindrical and conical filtration and washing, the bond between the metal of the catalyst and the ligand breaks, which plays a very good catalytic role in hydrogen peroxide, improves the oxidation selectivity of hydrogen peroxide, and increases the yield and purity of the product.

(3) The oxidation reaction rate is fast and the reaction time is short. The addition time of hydrogen peroxide solution has been shortened from the original 2 hours to the current 30 to 70 minutes, significantly reducing the reaction time.

(4) The quality of NS products obtained by the new process has been greatly improved

Due to the strong adsorption capacity of tert-butylamine, it is very easy for free amines to remain in the NS finished product. However, the new process adopts a combined cylinder and cone filtration and washing method in the synthesis and purification process, which solves the problem that amines adsorbed on semi-finished products are difficult to be thoroughly cleaned. The content of free amines in the resulting NS finished product is extremely low. Moreover, the new process uses hydrogen peroxide instead of sodium hypochlorite, and the resulting product contains no ash.

(5) The combined reaction of cylindrical and conical filtration and washing features rapid purification, high product yield and purity, low equipment requirements, and a promising industrial application prospect.

The process flow of the integrated machine for purification reaction, filtration and washing of rubber vulcanization accelerator NS

The cylindrical cone-type filtration and washing integrated machine is a rapid purification device for solid organic matter of rubber vulcanization accelerator NS. It is composed of an extraction liquid storage tank, a separator and a condenser, etc. Inside the multi-functional cylindrical cone-type filtration and washing equipment, there is a solid-liquid separation device, and at the lower end of the outside, there is a heating device. All operations of this purification device are carried out under fully automatic control, which can effectively improve the purification efficiency. It is simple to operate and a fully enclosed system, with a stable process and no harm to the human body or the environment. The specific steps of the integrated process of purification reaction, filtration and washing of rubber vulcanization accelerator NS are as follows:

(1) Add accelerator M and water to the reaction, filtration and washing integrated machine, and stir at room temperature for 10 minutes to ensure the raw materials are evenly dispersed.

(2) Then add tert-butylamine to the reaction, filtration and washing integrated machine, control the stirring speed at 30r/min and the temperature at 30℃, and mash it into salt.

(3) Add iron tetrasulfonyl phthalocyanine to the cylindrical cone-type filtration and washing two-in-one, stir evenly, then drop in hydrogen peroxide solution. Keep the drop time for 40 minutes, and continue the reaction for 0.5 hours after the drop is completed.

(4) After the reaction is completed, a series of post-treatments such as cooling, filtration, washing and drying can be carried out to obtain the NS finished product.

(5) After testing, it was found that the NS product contains no ash, the free amine content is 0.1%, the purity is 99.1%, and the yield rate in meters is 98.3%.

Compared with the existing industrial filtration devices, the rubber vulcanization accelerator NS purification reaction filtration and washing integrated machine has the following differences: fast reaction rate, short purification time, solving the problem of equipment blockage that is prone to occur during the filtration process of accelerator NS, effectively improving the convenience and efficiency of operation, and is especially suitable for the industrial purification of solid organic substances of rubber vulcanization accelerators.