Ethylene diamine carbamate

The elastomers based on vinylidene fluoride are saturated and cannot be vulcanized with sulphur. As with other saturated rubbers cross-linking can be brought about by irradiation and by the use of peroxides but the only agents of commercial importance until the 1970s were diamines and certain of their derivatives. Of particular importance have been the amine carbamates which are somewhat less reactive and less likely to scorch (premature vulcanization) during processing. Typical materials of this class are ethylene diamine carbamate (IX), hexamethylene diamine carbamate (X) and N,N -dicinnamylidene-1,6-hexane diamine (XI) ... 

The following procedure is based on the reaction of an aqueous solution of cobalt(II) chloride with the equivalent amount of (2-aminoethyl)carbamic acid, followed by oxidation with hydrogen peroxide and the subsequent formation of bis(ethylene-diamine)cobalt(III) ions. The bis(ethylenediamine)cobalt(lII) species are converted to the carbonato complex by reaction with lithium hydroxide and carbon dioxide. During the entire preparation a vigorous stream of carbon dioxide is bubbled through the reaction mixture. This procedure appears to be essential in order to minimize the formation of tris(ethylenediamine)cobalt(III) chloride as a by-product. However, the formation of a negligible amount of the tris salt cannot be avoided. The crude salts have a purity suitable for preparative purposes. The pure salts are obtained by recrystallization from aqueous solution. 

Lead is extractable from sea water by several procedures which are also suitable for the separation of other trace metals mentioned above. Highly selective methods are not known so far. Systems recommended for the extraction of lead are the resins Chelex-100 (chapter 2.3.3 S6), 2.3.461), 2.3.5 65), 2.3.9 86,87), ammonium pyrroli-dinedithiocarbamate/methyl isobutyl ketone (chapter 2.3.4 60,61), pyrrolidinedithio-carbamate with diethyldithiocarbamate/Freon TF (chapter 2.3.670), 2-Hydroxo-phenyl-(2)-azonaphtol (Hyphan) (chapter 2.3.671>, dithizone/chloroform (chapter 2.3.7 78)), and ethylene diamine triacetic acid/controlled pore glass (chapter 2.3.9 85)). 

Another prodrug of 54c is compound 55. Prodrug 55, which contains an aromatic and aliphatic bis-carbamate spacer, is activated by (3-glucuronidase (Scheme 23).86 A rapid cleavage of the glycosidic bond occurred (tj/2 = 6.6 minutes) with concomitant appearance of intermediate 55c, of which the ethylene diamine spacer cyclized with a half-life of 2 hours. The cytotoxicity of 55 against LoVo cells was about 50 times less than that of the corresponding phenol mustard 54c. 

A number of new 3,3 -ethylenebis(5-alkyl-l,3,5-thiadiazine-2-thiones) 250 have been synthesized via the dithio-carbamate route starting from ethylene diamine, as shown in Scheme 50 <2001MI305>. 

The reaction of ethylene diamine, carbon disulfide and dilute sodium hydroxide in a aqueous medium afforded disodium ethylenebis-dithiocarbamate, known by the tradename Nabam (8-11), and the treatment of the salt with zinc chloride furnished zinc ethyleneblsdithio-carbamate, known by the tradename Zlneb (10, 12, 13). 

Struktol WB 42 at a 1 % level, combined with 1 % stearic acid, is a good combination for general purpose use in peroxide-cured AEM ethylene acrylic elastomer compounds. Vamac AEM stocks using hexamethylene diamine carbamate (Diak No. 1) as the curative, requires 1% stearic acid plus 0.3% of a stearamide such as Armeen 18D from Akzo and 0.8% of Struktol WS 180. These chemicals act as coagents for mill release. Struktol WB 42, Struktol WS 180, and Armeen 18D also serve as mold release agents. 

In this article we are told that SEC Gummimischungen GMBH of Germany, a specialty compound distributor, has developed a hexamethylene diamine carbamate curing agent, HMDC-Batch , which is designed for curing fluoroelastomers and ethylene acrylic elastomers. 

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