- Preparation method of rubber vulcanization accelerator CBS
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The invention provides a preparation method of a rubber vulcanization accelerant CBS, and relates to the technical field of rubber vulcanization accelerants. The preparation method comprises the stepsof firstly dissolving 2-mercaptobenzothiazole in an organic solvent,adding a catalyst, fully mixing, and then dropwise adding cyclohexylamine for catalyzed oxidation reactions under a constant temperature and a constant pressure, introducing oxygento maintain the reactions at the constant pressure during the reactions, completing the reactions when the reaction pressure does not change for 30-40minute after the cyclohexylamine is added, and preparing the rubber vulcanization accelerant CBS; the organic solvent can well dissolve the CBS but does not chemically react with the 2-mercaptobenzothiazole and the cyclohexylamine. The preparation methodcan takethe oxygen as an oxidant to oxidize and synthesize the CBS under the effects of the catalyst,the generation of waste water containing nitrosamine carcinogens is eliminated,the cost ofoxidants is reduced, and the preparation method has the advantages of being green, environmentally friendly, energy-saving and economical.
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Paragraph 0059-0108
(2021/05/15)
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- Method for preparing sulfenamide rubber vulcanization accelerator by heterogeneous catalysis of oxidation of molecular oxygen
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The invention relates to a method for preparing a sulfenamide rubber vulcanization accelerator by heterogeneous catalysis of oxidation of molecular oxygen, and belongs to the field of chemical engineering. The method adopts heterogeneous metal cobalt-based nano material as a catalyst, in an oxygen or air environment, a sulfydryl compound and amine are reacted for 0.5-16 hours in an organic phase under the conditions that the atmospheric pressure is 1-7 and the temperature is 40-100 DEG C to prepare the sulfenamide rubber vulcanization accelerator. The catalyst has the characteristics of high catalytic activity, high reaction efficiency, low cost, easiness in obtaining and reusability; and the sulfenamide synthesis steps are simple, the conversion rate is high, byproducts are few, and the method is more suitable for industrial production.
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Paragraph 0025
(2021/08/07)
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- A comprehensive electrochemical study of 2-mercaptobenzoheterocyclic derivatives. Air-assisted electrochemical synthesis of new sulfonamide derivatives
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In this work, we have introduced a green air-assisted electrochemical method for the synthesis of new sulfonamide derivatives via oxidative coupling of heterocyclic thiols and amines. The synthetic method was designed based on the data collected from electrochemical oxidation of heterocyclic thiols, 2-mercaptobenzoxazole (MBO), 2-mercaptobenzothiazole (MBT) and 2-mercaptobenzimidazole (MBI) in the absence and presence of amines. The electrochemical results indicate that the oxidation of MBO and MBT lead to the formation of the corresponding dimers, which as an intermediate is essential for sulfonamide synthesis. The results also show that, in the time scale of our voltammetric experiments, oxidation of MBI does not lead to dimer formation. Our voltammetric studies suggest that the formed dimer is adsorbed on the electrode surface. The amount and intensity of adsorption depends on the type heterocyclic thiol, solvent, switching potential and solution pH. The mechanism of synthesis of sulfonamide compounds has been established based on the disappearing of the dimer reduction peak in the cyclic voltammogram of MBO in the presence of amines along with increasing the number of electrons transferred in this condition, as well as spectroscopic data of the products. These compounds have been successfully synthesized in water/ethanol mixture solutions in an undivided cell, at carbon rod electrodes, by constant current electrolysis at room temperature. The proposed method does not need to use toxic solvent, metal, catalyst and challenging workups. This method is easy to scale-up and the products have antibacterial activity.
- Youseflouei, Nesa,Alizadeh, Saber,Masoudi-Khoram, Mahmood,Nematollahi, Davood,Alizadeh, Hojjat
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- Method for synthesizing N-cyclohexyl-2-benzothiazolylsulfenamide through cobalt catalyst oxygen method
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The invention discloses a preparation method of a vulcanization accelerator, namely N-cyclohexyl-2-benzothiazolylsulfenamide. The preparation method comprises the steps that 2-mercaptobenzothiazole, cyclohexylamine and a cobalt catalyst are placed in a high pressure reactor, water is taken as a solvent for reaction, after reaction is completed, filtering, washing and drying are conducted, and thusthe N-cyclohexyl-2-benzothiazolylsulfenamide is obtained. The preparation method has the characteristics that raw materials are easy to obtain, the method is simple, the catalytic efficiency is high,the solvent is environmentally friendly, obtained products are high in purity, and aftertreatment is easy.
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Sheet 0021-0028
(2019/10/17)
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- Scalable electrochemical oxidant-and metal-free dehydrogenative coupling of S-H/N-H
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A practical and scalable electrochemical oxidation of S-H and N-H was developed. This oxidant- and catalyst-free electrochemical process enables S-N bond formation with inexpensive nickel electrodes in an undivided cell. This procedure exhibits broad substrate scopes and good functional-group compatibility. A 50 g scale oxidative coupling augurs well for industrial applications.
- Tang, Shanyu,Liu, Yan,Li, Longjia,Ren, Xuanhe,Li, Jiao,Yang, Guanyu,Li, Heng,Yuan, Bingxin
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supporting information
p. 1370 - 1374
(2019/02/14)
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- Synthetic method for delayed-action accelerator N-cyclohexyl-2-benzothiazolesulfenamide
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The invention discloses a synthetic method for the delayed-action accelerator N-cyclohexyl-2-benzothiazolesulfenamide. The synthetic method comprises the following steps: adding 2-thiomethoxybenzothiazole and a dichloromethane solution into a reaction vessel, controlling solution temperature, adding a potassium nitrate solution and lead dioxide powder, controlling a stirring speed, and carrying out a reaction; and carrying out cooling, carrying out standing for precipitatation, carrying out filtering, then carrying out washing with a sodium chloride solution a plurality of times, then carryingout washing with a propyl ether solution a plurality of times, carrying out recrystallization in a chloropropylene oxide solution and then carrying out dehydration with a dehydrating agent so as to obtain the finished N-cyclohexyl-2-benzothiazolesulfenamide.
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Paragraph 0012; 0015-0026
(2018/07/30)
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- Preparation method of N-cyclohexyl-2-benzothiazolesulfenamide
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The invention belongs to the technical field of fine chemical engineering, and concretely relates to an oxidant-free preparation method of N-cyclohexyl-2-benzothiazolesulfenamide (CBS). The CBS is synthesized from benzothiazole disulfide (a sulfuration promoter DM) and cyclohexylamine by using an inorganic or organic alkaline catalyst, no oxidant is needed in the reaction process, the added catalyst can be repeatedly used, and the addition amount of the catalyst is 5-30% of the weight of benzothiazole disulfide. The yield of the CBS product synthesized through the method stabilizes in a range of 98-99.5, methanol insoluble substances in the product are stable, the lowest content of the methanol insoluble substances is 0.1%, and the highest content of the methanol insoluble substances is 0.22%, and no wastewater is generated in the process, so the method is suitable for industrial production.
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Paragraph 0015; 0016; 0017; 0017; 0019; 0020; 0021
(2017/02/17)
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- Reusable cobalt-phthalocyanine in water: Efficient catalytic aerobic oxidative coupling of thiols to construct S-N/S-S bonds
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A new aerobic oxidative coupling of thiols in water to construct sulfenamides or disulfides was developed, utilizing cobalt(ii)phthalocyanine-tetra-sodium sulfonate as the catalyst and O2 as the oxidant. The mother liquor could be recycled up to 20 times with negligible loss of activity and only a minor decrease of product yield.
- Dou, Yingchao,Huang, Xin,Wang, Hao,Yang, Liting,Li, Heng,Yuan, Bingxin,Yang, Guanyu
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supporting information
p. 2491 - 2495
(2017/07/17)
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- Production method of N-cyclohexyl-2-benzothiazole sulfenamide
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The invention discloses a production method of N-cyclohexyl-2-benzothiazole sulfonamide in the technical field of preparation of N-cyclohexyl-2-benzothiazole sulfonamide. The N-cyclohexyl-2-benzothiazole sulfonamide is prepared by firstly adding 15-17% of cyclohexane in an oxidizing tank, and stirring the cyclohexane solution and adding 2-thiol group benzothiazole to form a mixed solution, wherein the amine ratio of cyclohexane and 2-thiol group benzothiazole is 2.3; secondly fully stirring the mixed solution, and then cooling to 35 DEG C, slowly dropwise adding sodium hypochlorite solution with concentration of 5% in the mixed solution, and forming reaction fluid, until the N-cyclohexyl-2-benzothiazole sulfonamide is generated, and yellow grain of 2-thiol group benzothiazole in the reaction fluid is disappeared; thirdly, stirring the oxidized reaction fluid and pouring to a suction filtration tank to filter; washing the filtered N-cyclohexyl-2-benzothiazole sulfonamide by hot water until the neutral; performing centrifugal drying and blowing by hot wind, and obtaining the finished product. Through optimizing the production process, the generation rate of the target matter is improved and waste of reactant is reduced.
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Paragraph 0031; 0032; 0033; 0036; 0037; 0038; 0039
(2017/04/03)
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- Plasma oxidation process for synthesizing rubber accelerator CBS
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The invention discloses a method for synthesizing a rubber accelerator CBS (N-cyclohexyl-2-benzothiazolesulfenamide) through a plasma oxidation process. The synthesis method includes the following steps: uniformly stirring and mixing 2-mercaptobenzothiazole, a proper amount of deionized water and a nonionic surfactant in a reaction kettle; adding a cyclohexylamine aqueous solution into the reaction kettle under room temperature stirring, and uniformly mixing for 1h; heating until the temperature is 35-45DEG C, slowly and uniformly introducing compressed air or oxygen (accounting for 110-300% of a theoretical amount) active oxygen generated by an ozone plasma generator, and carrying out an oxidation reaction for 1-4h to reach an end point; and carrying out pumping filtration after a white product precipitates, recycling the above obtained mother liquor, washing the product with water, and drying to obtain the CBS. The method has the advantages of simple production process, stability, maturity, security, environmental protection, energy saving, no pollution, good product quality (initial melting point of above 99DEG C), high yield (98%), low production cost and easy industrialization. The CBS is a commonly-used highly-active aftereffect accelerator, has the advantages of excellent anti-scorch performance, and short curing time, and can be widely used in the production industries of tires, rubber overshoes, rubber hoses, rubber belts, cables and the like.
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Paragraph 0024; 0025; 0028; 0029
(2017/01/12)
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- Fluoroalkane thioheterocyclic derivatives and their antitumor activity
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Two series of novel trifluorobutenyl derivatives of heterocyclic with convenient and efficient synthesis methods and their antitumor activity on three cell lines have been reported for the first time. The derivatives were synthesized by the nucleophilic substitution between 4-bromo-1,1,2-trifluorobutene-1-ene and commercially available nitrogen-containing heterocycles with sulfydryl or monosubstituted malononitrile. The twenty-four new compounds were characterized by 1HNMR, 13CNMR and HR-MS. Totally, thirty-seven compounds were evaluated for the antitumor activity on three cancer cell lines (SH-SY5Y, MCF-7 andHepG2) using conventional MTT assay. The pharmacological results indicated that the compounds 3c, 3h, 4c, 8, 9, 10 and 11 showed potent to moderate antitumor activity against three cancer cell lines, with IC50 values ranging between 0.4 μ M and 41.5μ M. Eventhough they had less active than the reference compound taxol against MCF-7 and HepG2 lines, but they were better than the reference compound noscapine against SH-SY5Y cells, especiallythe compound 3h with a IC50 value of 0.4 μM.
- Li, Guangxiao,Sun, Qian,Wang, Dongling,Xu, Ying,Zhuang, Jingjing,Zhang, Qian,Sun, Dequn
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p. 423 - 430
(2015/03/14)
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- Process for the preparation of benzthiazolylsulfenamides by reacting a primary amine with alkali salts of mercaptobenzthiazole in the presence of hydrogene peroxide and alkalimetal hypochlorite
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A process for the production of benzothiazolyl sulfenamides by reaction of a primary amine and alkali metal salts of mercaptobenzothiazole in the presence of hydrogen peroxide dosed in over a period greater than or equal to 2 hours followed by the addition of the alkali metal hypochlorite over an at least 10 minute period and adjustment of the pH to 11.5-12 at the end of the reaction. A process for the production of benzothiazolyl sulfenamides (I) by reaction of a primary amine with alkali metal salts of mercaptobenzothiazole in the presence of hydrogen peroxide and alkali metal hypochlorites comprises reaction of an aqueous solution of a metal salt of mercaptobenzothiazole with the primary amine in the presence of up to 90 mol.% hydrogen peroxide (with respect to the mercaptobenzothiazole) at pH 10.0-11.0 whereby the hydrogen peroxide is dosed in over a period greater than or equal to 2 hours followed by the addition of the alkali metal hypochlorite over an at least 10 minute period and adjustment of the pH to 11.5-12 at the end of the reaction whereby the amount of primary amine added is 100-500 mol.% and the sum of hydrogen peroxide and alkali metal hypochlorite added is up to 130 mol.% (with respect to the amount of the alkali metal salt of the mercaptobenzthiazole).
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Page column 7
(2008/06/13)
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- Process for preparing benzothiazolesulphenamides
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Benzothiazolesulphenamides can be prepared in high yield and purity from dibenzothiazolyl disulphide and a primary or secondary amine in the absence of an oxidizing agent in a water-immiscible organic solvent and in the presence of aqueous alkali by presenting a solution of the amine in the organic solvent and adding dibenzothiazolyl disulphide and aqueous alkali either simultaneously or in succession.
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- Process for the production of sulfenamides
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Benzothiazole-2-sulfenamides are prepared by reacting a 2-mercaptobenzothiazole and a primary or secondary amine with oxygen in the presence of a catalyst, for example a metal phthalocyanine, in a reaction medium consisting of (i) a mixture of the amine and water in which the amount of water at the outset of the reaction is from 0.2 to 20% by weight of the mixture, or (ii) a mixture as defined in (i) diluted with an inert organic solvent miscible with the mixture, in a proportion of up to two parts by weight of the inert organic solvent per part by weight of the mixture.
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- Manufacture of sulfenamides
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Processes for the manufacture of sulfenamides by the oxidation of a mixture of 2-mercaptobenzothiazole and the appropriate amine in a critical amount of water and/or organic solvent produces a pure product of good quality and high yield. The amount of water should be in the range of from 10 to 30% by weight based on the total reaction mixture.
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- Process for the preparation of thiazolesulphenamides
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Thiazolesulphenamides, useful as rubber vulcanization accelerators, are made by reaction of a 2-mercapto-thiazole or a 2,2'-dithiazolyl disulphide with ammonia or a primary or secondary amine in the presence of oxygen and a copper catalyst of specified kind.
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