Preparation of N-tert-butyl-2-benzothiazole sulfenamide_Kain Industrial Additive

Background and overview^[1]

N-tert-butyl-2-benzothiazole sulfenamide is a commonly used post-effect accelerator. It is very safe at operating temperature, has good scorch resistance and high tensile strength, and can improve synthesis The proportion of rubber used and the amount of filler carbon black are increased. It is called a “standard accelerator” and is one of the leading varieties of sulfenamide vulcanization accelerators. It is mainly used for natural rubber, butadiene rubber, styrene-butadiene rubber, isopropyl rubber, etc. In penta rubber.

Preparation^[1-2]

Report 1,

In the first step, mix 30ml of 25% sulfuric acid and 200ml of toluene to prepare a mother liquor, then add 84g of 2-mercaptobenzothiazole (MBT or M), control the reaction temperature to 20-50°C and normal pressure Then, stir at a speed of 800 rpm, add 32 ml of 27.5% hydrogen peroxide dropwise at a rate of 1.5 ml/min, continue stirring for 10 min after the dropwise addition is completed, and filter to obtain a solid DM and toluene mixture with a wet weight of 103 g. The liquid is separated. , the lower water phase is 60ml, the upper toluene phase is 180ml, the water phase is evaporated and concentrated to 30ml, mixed with the toluene phase, and 20ml of the toluene phase is added to prepare the next batch of DM.

In the second step, mix 103g solid DM and toluene mixture with 100ml tert-butylamine and 200ml toluene and beat. Control the reaction temperature to 40-50°C and stir at a stirring speed of 800 rpm under normal pressure. Then add 120ml of 9% hydrogen peroxide dropwise at a speed of 2ml/min. After the dropwise addition is completed, let it stand for liquid separation. The upper toluene phase is distilled under reduced pressure to obtain 220ml of condensate, which is a mixture of toluene and tert-butylamine, which can be reused, and the solid obtained is crude NS; 140ml of the lower aqueous phase contains 15±2% tert-butylamine for preliminary washing of the crude NS, and 200ml of clean water is used for the second time Wash the crude NS and then distill it under normal pressure to obtain 60ml of fractions below 100°C, which are determined to contain 30.5% of tert-butylamine and can be recycled after rectification; the residual liquid is filtered to obtain 270ml of recovered water with a COD of 175mgO/L and can be used again. , the filter residue is 1.5g after drying and needs to be processed centrally. The crude NS was washed and dried to obtain 116 g of NS white solid, with NS purity of 99.5%.

Report 2,

1. Add accelerator 2-mercaptobenzothiazole, catalyst and water to a three-necked flask equipped with a thermometer, spherical reflux condenser and constant pressure dropping funnel, add emulsifier to the water phase, and turn on magnetic stirring Turn on the switch and start stirring;

2. Add tert-butylamine dropwise through the constant pressure dropping funnel. After the dropwise addition is completed, raise the temperature to 65°C, add hydrogen peroxide dropwise, finish dropping in 45 minutes, and react with constant temperature stirring for 1 hour;

3. After the reaction is completed, cool the solid matter to precipitate, filter, wash and dry to obtain N-tert-butyl-2-benzothiazole sulfenamide.

Preparation of paste^[3]

CN201810806372.1 discloses N-tert-butyl-2-benzothiazole sulfenamide paste and its preparation method. N-tert-butyl-2-benzothiazole sulfenamide paste includes high-viscosity long-chain chlorinated paraffin, DBU cresolate and N-tert-butyl-2-benzothiazole sulfenamide powder; the preparation method includes: 1. Evenly mix N-tert-butyl-2-benzothiazole sulfenamide powder with high-viscosity long-chain chlorinated paraffin and DBU cresolate in a kneader discharging under the screw; 2. Mix the mixture in the kneader It is further processed through the discharging screw at the lower part of the kneader to obtain N-tert-butyl-2-benzothiazole sulfenamide paste. The N-tert-butyl-2-benzothiazole sulfenamide paste of the present invention has the advantages of high dispersion, easy uniform mixing, no dust generation, simple production operation, high efficiency, and is suitable for industrial production.

Masterbatch preparation^[4]

CN201510307585.6 discloses a kind of N-tert-butyl-2-benzothiazole sulfenamide pre-dispersed masterbatch. In parts by weight, the composition of the masterbatch is: N-tert-butyl- 75 to 81 parts of 2-benzothiazole sulfenamide, 9 to 15 parts of rubber matrix, 7 to 9 parts of naphthenic oil, 1 part of fatty acid alcohol ester, and 1 part of triethanolamine; the rubber matrix is ​​composed of the main rubber and processing aids. The preparation method of the invention is simple and easy to operate. The rubber matrix is ​​prepared by pre-mixing during preparation, which can effectively reduce the mixing time required for subsequent preparation of masterbatch particles. The prepared masterbatch particles are free of impurities and dust and can effectively retain N- The original activity of tert-butyl-2-benzothiazole sulfenamide does not agglomerate at room temperature, is easy to mix and mix, has good fluidity, no dust flying, will not cause skin allergies to operators, and has high raw material utilization. ; After the ingredients are mixed, they are evenly dispersed in rubber products, which can ensure the production efficiency and quality of rubber products, and is of great significance to the sustainable development of the rubber manufacturing industry.

References

[1][Chinese invention] CN201710990575.6 An environmentally friendly N-tert-butyl-2-benzothiazole sulfenamide (NS) synthesis process

[2][Chinese invention] CN201310520507.5 Preparation method of rubber accelerator N-tert-butyl-2-benzothiazole sulfenamide

[3][Chinese invention] CN201810806372.1N-tert-butyl-2-benzothiazole sulfenamide paste and preparation method thereof

[4][China invention, China invention authorization] CN201510307585.6N-tert-butyl-2-benzothiazole sulfenamide predispersed masterbatch particles and preparation method thereof