Mercaptobenzothiazole disulfide

Due to the vulcanization process, finished rubber products contain only small amounts of TBBS or synthesis by-products (benzothiazole, 2-mercaptbenzothiazole and 2-mercaptobenzothiazole disulfide). Release to die environment of these chemicals may occur during die use of rubber products. Fugacity model (Mackay level III) data suggest that it would mostly distribute to soil (if released to the air or soil compartments) and to water (if released to the water compartment). 

High-tensile-strength butyl compounds generally use FEF- or GPF-grade carbon blacks. Vulcanization systems tend to be based on thiazole accelerators such as mercaptobenzothiazole disulfide (MBTS) and thiuram accelerators such as tetramethylthiuram disulfide (TMTD). Low-tensile-sfrengfh compounds will use a clay or silica reinforcing filler in place of carbon black. 

Benzothiazyl-2-diisopropyl sulfenamide. See Diisopropyl benzothiazole sulfenamide Benzothiazyl disulfide CAS 120-78-5 EINECS/ELINCS 204-424-9 Synonyms Benzothiazole disulfide Benzothiazolyl disulfide 2-Benzothiazolyl disulfide Bis(benzothiazolyl) disulfide Di-2-benzothiazolyldisulfide Dibenzothiazyl disulfide 2,2 -Dibenzothiazyl disulfide 2,2 -Dithiobisbenzothiazole MBTS 2-Mercaptobenzothiazole disulfide 2-Mercaptobenzothiazyldisulfide Mercaptobenzthiazyl ether Empirical C14H8N2S4 Formula (C6H4SCN)2S2... 

Mercaptobenzothiazole disulfide. See Benzothiazyl disulfide 2-Mercaptobenzothiazole sodium deriv. 2-Mercaptobenzothiazole sodium salt. See Sodium 2-mercaptobenzothiazole 2-Mercaptobenzothiazole zinc salt. See Zinc 2-mercaptobenzothiazole 2-Mercaptobenzothiazyldisulfide Mercaptobenzthiazyl ether. See Benzothiazyl disulfide... 

Standard rubber industry accelerators (e.g., CBS, diphenyl guanidine, mercaptobenzothiazole disulfide (MBTS) and zinc diethyl carbamate these can be used with or without other rubber chemicals, such as peptisers)... 

The first delayed action accelerators were introduced in 1925 with the development of 2-mercaptobenzothiazole (MET) and 2-mercaptobenzothiazole disulfide (or 2,2"-dithiobisbenzothiazole) (MBTS) (a.5-a.7). Even more delayed action and yet faster-curing vulcanisation became possible in 1937 with the introduction of the first commercial benzothiazolesulfenamide accelerator (a.8, a.9). Further progress was made in 1968 with the introduction (a. 10) of pre-vulcanisation inhibitor (PVI), A-cyclohexylthiophthalimide (CTP), which can be used in small concentrations together with benzothiazole sulfenamide accelerators. The history of the progress toward faster vulcanisation with better control of premature vulcanisation or scorch is illustrated by Figure 2. 

MET, mercaptobenzothiazole TMTM, tetramethylthiuram mono sulfide TMTD, tetramethylthiuram disulfide and CBTS, Al-cyclohexyl-2-benzothiazole... 

All compositions contain EPDM, 100 phr zinc oxide, 5 phr stearic acid, 1 phr antioxidant, 1 phr 2-mercaptobenzothiazole (accelerator), 1.5 phr tetramethyl thiuram disulfide (accelerator), 1 phr and sulfur, 1.5 phr. 

The electrooxidation of thiophenol [19], 2-mercaptobenzothiazole [22], 6- and 2-thiopurine [23], 2-thiopyridine [24] results in their disulfide derivatives in good yields. Bifunctional compound, 2,6-purinedi-thiol [23] can form first a 6,6 -disulflde (4), and then, by subsequent oxidation of the latter, give a cyclic product with two S - S bridges (Scheme 5). 

Captax (Structure 15.21) is used to the extent of 1% with hevea rubber and accounts for the major part of the over 30,000 t of accelerators used annually in the United States. Other accelerators widely used include 2-mercaptobenzothiazole sulfenamide (Santocure Structure 15.22), used for the vulcanization of SBR dithiocarbamates and thiuram disulfides. Thiuram disulfide (Structure 15.23) is a member of a group called ultra-accelerators, which allow the curing of rubber at moderate temperatures and may be used in the absence of sulfur. 

The second important class of accelerators are zinc dialkyldithiocarbamates (XXI). These are more active with faster vulcanization rates than the 2-mercaptobenzothiazole sulfena-mides. Also, activators are not usually needed since the zinc is incorporated into the accelerator molecule. Tetralkylthiuram disulfides (XXII) in combination with activators S... 

Fig. 13. Relationship of nitrile rubber cure systems where DCP is dicumyl peroxide MBTS, benzothiazyl disulfide ZnDMD, zinc dirnethyldithiocarbamate MBT, mercaptobenzothiazole TMTM, tetramethylthiuram mono sulfide TMTD, tetramethylthiuram disulfide and CBTS, iV-cyclobexyl-2-benzothiazole...

Co-exposures 4,4 -Methylene bis (2-methylaniline) (2B) Magenta (2B) Safranine T or/ oNitrotoluene (3) 2,5-Diaminotoluene (3) Aniline (3) ori/io-Amino-azotoluene (2B) Multiple ejqjosures including 4-chloro-o/t/io-toluidine and 4-chloroacetyl-or/Zio-toluidine A/ Acetyl-or//io-toluidine 6-Chloro-or//io-toluidine 4-Chloro-or//io-toluidine (2A) Aniline (3) Hydroquinone (3) Toluene (3) Carbon disulfide Sulfur Benzothiazole 4-Aminobiphenyl (contaminant) (1) 2-Mercaptobenzothiazole (Ward et al, 1996) (Proprietary chemical) Aniline (3) 2-Mercaptobenzothiazole Phenyl-p-naphthylamine (3)... 

Tellurium dimethylthiocarbamate in combination with mercaptobenzothiazole, with or without tetramethylthiuram disulfide, is the fastest known accelerator for butyl mbber. It is used extensively in butyl tubes for buses and similar vehicles and in other butyl applications (see Elastomers, synthetic Rubber, natural). 

The chemistry of the vulcanization of rubber is complex. The reaction of rubber with sulfur is markedly expedited by substances called accelerators, of which those commonly known as mercaptobenzothiazole and tetramethyl-thiuram disulfide are examples ... 

Curing recipe Copolymer containing 3 mole % allyl glycidyl ether 100 parts HAF black 0 or 40 parts per hundred of rubber (phr) ZnO 5.0 phr stearic acid 2.0 phr sulfur 2.0 phr mercaptobenzothiazole 1.0 tetramethylthiuram disulfide 1.0 phr... 

This dependence of product distribution on reaction conditions is also evident when 2-mercaptobenzothiazole is oxidized under acidic conditions. The material will form the disulfide provided a stoichiometric amount of hydrogen peroxide is employed.364 However, when excess hydrogen peroxide is used, the sulfinic acid will be formed, which upon acidification liberates sulfur dioxide to give the benzothiazole.365 Thus 2-mercaptothiazoles, under certain conditions, will undergo desulfurization, which is an important step in the preparation of chlormethiazol,366 a vitamin Bi intermediate (Figure 3.94). 

Accelerators are chemical compounds that iacrease the rate of cure and improve the physical properties of the compound. As a class, they are as important as the vulcanising agent itself Without the accelerator, curing requires hours or even days to achieve acceptable levels. Aldehyde amines, thiocarbamates, thiuram sulfides, guanidines, and thiasoles are all classified as accelerators. By far, the most widely used are the thiazoles, represented by mercaptobenzothiazole (MBT and benzothiazyl disulfide (MBTS). 

Electrochemical oxidation of 2-mercaptobenzothiazole proceeds via the radical 213 which dimerizes to the corresponding disulfide this electrochemical reaction is of synthetic value in preparing the disulfide. ... 

A larger amount of sulfur added to natural rubber (20-30%) generates a different product, vulcanite. Besides sulfur, during the vulcanization process other chemical compounds are commonly added to rubber. One group of such compounds consists of vulcanization accelerators (A in the previous scheme). Substances such as diphenylguanidine, mercaptobenzothiazole, tetramethythiuram disulfide, N-oxydiethylene-2-benzothiazolylsulfenamide, and cyclohexylbenzothiazolylsulfenamide are utilized as accelerators. 

Accelerators, e.g. zinc oxide and fatty acids, increase the rate of vulcanisation of rubber by sulfur and they reduce the amount of sulfur required from 10% to <3%. Certain sulfur-donating accelerators, like thiuram disulfides (1) and mercaptobenzothiazole (2), will effect vulcanisation without added sulfur to yield products with greatly enhanced ageing properties.1... 

The vulcanization accelerators include the thiazole 2-mercaptobenzothiazole (MBT) (169), and its derivative benzothiazole disulfide (dibenzoythiazyl disulfide, 2,2 -dithiobis (benzothiazole), MBTS) (170). Organic accelerators enable reduction in time of vulcanization, more effective use of sulfur in formation of cross-links and use of low processing temperatures. MBTS delays vulcanization, when compared with MBT alone. They are used in production of conveyor belts, footware, etc. The 2-mercaptobenzothiazole zinc salt (MBTZ) (171) is also important, and is used in latex products. Other sulfur donors include 2-morpholinodithiobenzothiazole, 2-(4-morpholinyldithio)benzothiazole (MBSS, MORFAX) (172). 

TBBS does not ionize at environmental pHs, is not readily biodegradable, but hydrolyzes in less than 1 day at pH 9 or less. The identified hydrolysis products mercaptobenzothiazole, di(benzothiazoyl2)disulfide, t-butylamine, and benzothiazoleare are non-volatile, with a low potential for bioaccumulation, and are not readily biodegradable. Indirect photo-oxidation by hydroxy radicals is predicted with a half-life estimated at 2.8 hours. Log Pow of 3.9 at room temperature. 

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