Thiocarbamide, reaction with

THIOCARBAMIDE (62-56-6) Aqueous solution is a base. Violent reaction with acrolein, strong acids. Incompatible with acrylaldehyde, hydrogen peroxide, metal salts. Aqueous solution incompatible with organic anhydrides, acrylates, alcohols, aldehydes, alkylene oxides, substituted allyls, cresols, caprolactam solution, epichlorohydrin, ethylene dichloride, glycols, hydrogen peroxide, isocyanates, ketones, mtdeic anhydride, nitrates, nitromethane, phenols, vinyl acetate. 

The reaction products of thiocarbamide derivatives with cumylperoxide radicals exhibit a secondary inhibiting effect. 

Table 9.3 Kinetic parameters for the reaction of thiocarbamide derivatives with cumylperoxide radicals and cumyl hydroperoxide as well as the induction periods in cumyl autoxidation in presence of given antioxidants...

The research allows one to draw several conclusions. First, these thiocarbamides function as combined-action antioxidants, and some of them strongly inhibit hydrocarbon oxidation. Second, as shown in Fig. 9.8, some of the traditional inhibitors we have synthesized after their reaction with peroxide radicals are unable to catalytically decompose hydroperoxides. Third, in the process of hydrocarbon oxidation, peroxide radicals are earlier oxidation products than hydroperoxides, hence these antioxidants will be consumed following the reaction with peroxide radicals. 

The reaction is carried out in both acidic and basic media. Thus, for example, the interaction of 4-diethylaminobut-3-en-2-one with thiocarbamide is performed at 75°C for 30 h (EtOK, EtOH) to result in 54% yield of the major product. The existence of two tautomers 274 and 275 was proved for 2-mercapto-4-methylpyrimidine (Y = S) by IR and H NMR spectroscopy (76ZOR2063). 

In 1884, Emerson-Reynolds reported deposition of PbS films by reaction between thiourea (thiocarbamide) and alkaline lead tartrate, where the metallic sulphide. .. became firmly attached as a specular layer to the sides of the vessel [6], A wide range of substrates, apart from that just mentioned (a glass beaker), was successfully used for this deposition porcelain, ebonite, iron, steel, and brass were specifically mentioned. Even more important, the deposits were very adherent, as quantified by their ability to withstand considerable friction with a wash-leather, and under this treatment take a fine polish. ... 

Another method of preparation consists in heating carbon disulphide with ammonium carbonate in a sealed tube. The other product of this reaction is ammonium thiocyanate. The yield of thiocarbamide by this method is stated to be much below the theoretical value.6... 

A delicate colour-reaction for osmium consists in warming a solution containing the metal, in the form of its tetroxide or as chlorosmate, with thiocarbamide in excess, together with a few drops of hydrochloric acid. The presence of osmium is indicated by the development of a... 

In further studies of the synthesis of porphobilinogen and isoporphobilinogen, a-free pyrroles (prepared by Knorr type syntheses) were aminomethylated by the Tschemiak-Einhom reaction, for example, treatment with A -hydroxy-methylchloroacetamide in hot ethanolic hydrogen chloride. The resulting chloro-acetylamino derivatives (14) could be reduced catalytically to the acetylamino-methyl pyrroles (15). In related studies an acetylaminomethyl pyrrole (16b) was also prepared by treatment of 2,4-dimethylpyirole with acetyl thiocyanate followed by Raney nickel reduction of the intermediate acetyl thiocarbamide (16a). 

Reaction of o-phenylenediamine with phenyl isothiocyanate in CCI4 gave thiocarbamide 37 which underwent oxidative cyclization to benzothiadiazine 38 upon treatment with ethanolic iodine followed by basification with ammonium hydroxide solution (Scheme 2). Analogous results were obtained using a variety of ring-substituted phenyl isothiocyanates as well as /-butyl isothiocyanate in this sequence, with overall yields ranging from 69% to 87% <2004JIC775>. 

The kinetic parameters for reaction of the thiocarbamides with cumylperoxide radicals and cumyl hydroperoxide are also consistent with M-benzyl-A[ -(3-thiethanyl) thiocarbamide being faster in both oxidation chain termination (reacting with cumylperoxide radicals) and in catalytic decomposition of cumyl hydroperoxide. It was also shown that A -benzyl-V-(3-thiethanyl) thiocarbamide inhibits cumene autoxidation better than the other thiocarbamide derivatives when used in lower concentrations than the latter. 

---