Zinc dimethyl-dithiocarbamate

The TMTD reacts with the rubber hydrocarbon by a first order process at a rate 2-4 times greater than by which the zinc dimethyl dithiocarbamate is produced. 

Whilst it has been established (on the basis of chemical probe studies, use of model compounds and consideration of cross-link stability) that in the above system the isocyanate reacts with the secondary amine group it has been found that in the presence of zinc dimethyl dithiocarbamate some reaction also occurs at the phenolic hydroxyl group. 

Such a mono-adduct may be used in conjunction with the zinc dimethyl dithiocarbamate as a catalyst and calcium oxide as a drying agent and stabilizer. 

Wo 1. Tungsten (lUPAC) ZDMC Zinc dimethyl dithiocarbamate (WTR)... 

The vulcanisation of cis,cis,cis-l,5,9-cyclodecatriene (as a model compound for true polybutadiene vulcanisates) by means of l-oxa-4,5-dithiacycloheptane, zinc dimethyl dithiocarbamate and 1,12-diaminododecane was studied using several one-dimensional and two-dimensional NMR techniques in order to determine crosslinking sequence and overall molecular structure. As a result of the relatively high solubility of the products, typical solution 2D NMR pulse sequences could be applied, offering a framework of reference for the subsequent solid state NMR studies on true vulcanisates. 20 refs. 

A study in Japan looked at the migration of dimethylamine (DMA) into water and hydrochloric acid from 25 rubber articles (including stoppers, chopping boards, spatulas and teats). After one hour of refluxing, the water extracts contained 3 to 1280 mg of DMA per kg of rubber. The study also showed that the thiuram accelerators that were present (TMTD and TMTM) were almost totally decomposed to DMA (a nitrosatable substance). However, in the case of dimethyl dithiocarbamate salts (sodium, zinc, copper and lead examples were included), the decomposition to DMA depended on the solvent used and the salt compound. 

These are easily prepared by the reaction of amines with carbon disulfide (1) in the presence of alkali (Scheme 17).2 The synthesis of dithiocarba mates (4) was first reported by Debus in 1850. Dithiocarba mates (4) form metal chelates, and sodium dimethyl dithiocarbamate is used in quantitative inorganic analysis for the estimation of metals, e.g. copper and zinc. Dithiocarba mates are also employed as vulcanisation accelerators and antioxidants in the rubber industry, and as agricultural fungicides.3 The parent dithiocarbamic acids are unstable, decomposing to thiocyanic acid and hydrogen sulfide however, the salts and esters are stable compounds. Dithiocarba mates (4) are oxidised by mild oxidants to the thiuram disulfides (38) (Scheme 17). 

Penicillamine (D-(3,(3-dimethylcysteine) is an effective chelator of copper, mercury, zinc and lead which promotes the excretion of these metals in the urine. It is clinically used in patients with Wilson s disease, with rheumatoid arthritis and with heavy-metal intoxications. Ziram and ferbam are the zinc and the iron salts respectively of dimethyl-dithiocarbamic acid (Figure 20.44). They are widely used as selective fungicides in agriculture. Pyrithione (1 -hydroxy-2(l//)-pyridinethione), as its zinc salt is used in dermatology as antiseborrheic. 

Pesticides as a class contain 2 widely quoted examples of ambiguity between mutagenic activity and carcinogenicity. Dichlorvos (2,2-dichlorovinyl dimethyl phosphate), an organophosphate insecticide, and ziram (bis(dimethyldithio-carbamate)zinc), a dithiocarbamate fungicide, are confirmed bacterial mutagens [13]. 

Bismate Powd., Bismate Rodform . See Bismuth dimethyl dithiocarbamate Bis (mercaptoacetate) dioctyltin bis (isooctyl) ester. See Dioctyltin diisooctylthioglycollate Bis (mercaptobenzimidazolato) zinc. See Zinc 2-mercaptobenzimidazole Bis (mercaptobenzothiazolato) zinc. See Zinc 2-mercaptobenzothiazole... 

N-Cyclohexyl-2-benzothiazolesulfenamide 1,3-Dibutylthiourea Dicyclohexylbenzothiazyl-2-sulfenamide Dimethyl diphenyl thiuram disulfide 2,6-Dimethylmorpholine Diphenylamine 4,4 -Dithiodimorpholine 2-Ethylbutyraldehyde Ethyl morpholine Formaldehyde aniline 2,6-Lutidine N-Nitrosodimethylamine Paraldehyde p-Quinone dioxime Selenium Selenium dimethyidithiocarbamate Sodium diethyidithiocarbamate Sodium dimethyidithiocarbamate Sodium nitrite N,N,N, N -Tetrabenzylthiuram disulfide Tetraisobutylthiuram disulfide Tetramethylthiuram disulfide Thiocarbamyl sulfenamide Thiophenol Thiourea Triethanolamine Triethylamine Triethylenetetramine n-Valeraldehyde Zinc dialkyl dithiophosphate Zinc diamyidithiocarbamate Zinc dibenzyl dithiocarbamate Zinc diisobutyidithiocarbamate Zinc isopropyl xanthate Zinc 2-mercaptobenzothiazole Zinc oxide Zinc-N-pentamethylene dithiocarbamate Zinc peroxide accelerator, rubber articles for repeated use food-contact... 

Transition metal atoms coordinated by dithiocarbamate ligands through four sulfur atoms have both electronic (free d-orbitals) and steric (free octahedral sites) propensity to form adducts with nitrogen bases, since nitrogen atoms have one sp -hybrid orbital, which is occupied by the lone pair of stereochem-ically active electrons. To characterize newly prepared adducts of dimethyl-, diethyl- and morpholinedithiocarbamate zinc(II) complexes with cyclic N-donor bases, such as pyridine, piperidine, hexamethyleneimine and morpholine, compounds 28-35 have been prepared and studied by and CP/MAS... 

Rubber Chemistry and Technology 68, No.4, Sept/Oct.1995, p.563-72 SULPHUR VULCANISATION OF SIMPLE MODEL OLEFINS. IV. VULCANISATIONS OF 2,3-DIMETHYL-2-BUTENE WITH TMTD AND ACTIVATED ZINC DITHIOCARBAMATE/ XANTHATE ACCELERATORS AT DIFFERENT TEMPERATURES... 

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