Model benzenethiol

The polycondensation of dibromomethane with bis(benzenethiol) instead of bisphenol also shows stoichiometrically imbalanced polymerization behavior (Scheme 63) [253]. When 1.5 equivalents of dibromomethane was reacted with dithiol in NMP at 75 °C for 4 h, polysulfide with the maximum inherent viscosity (//jn, = 0.50 dbg ) was obtained. On the basis of the model reaction, a reactive intermediate, in which a bromine in dibromomethane is substituted with the mercapto group of the monomer, is estimated to be 61 times more reactive than dibromomethane. 

In relation to HDS catalysis, C-S bond cleavage of thiols has also been extensively investigated. Co/Mo/S cluster shown in Scheme 3.79 reacts with benzenethiol to give a new /r-sulhdo cluster by releasing benzene. Such reactions are also regarded as one of the model reactions of heterogeneous HDS catalyst... 

Turk T, Resch U, Fox M A, and Vogler A, (1992) Cadmium Benzenethiolate Clusters of Various Size Molecular Models for Metal Chalcogenide Semiconductors. J Phys Chem 96 3818 Fischer Ch-H and Henglein A, (1989) Photochemistry of Colloidal Semiconductors. 31. Preparation and Photolysis of CdS Sols in Organic Solvents. J Phys Chem 93 5578... 

Fig.l3 Topi Structures of oligo(phen)dene-ethynylene)benzenethiols 10-13 [131,132]. Bottom left STM image of 12 on Au(lll)/mica. Bottom righti top-down view of a 2(V3 x /3)R30° model for SAMs of 12 on Au(lll). Ovals indicate a possible dimerisation scheme. Reprinted with permission from [131]. Copyright (1996) American Chemical Society... 

Perng [21] and Perng and co-workers [22] studied the thermal decomposition behaviour of polyphenylene sulfide (PPS) by stepwise Py-GC-MS and TGA-MS techniques. The mechanism and kinetic model of the pyrolytic behaviour of PPS was investigated by TG-MS from room temperature to 900 °C. The mechanism indicated apparently one-stage pyrolysis, principally by depolymerisation, main chain random scission and carbonisation. The initial scission of PPS was depolymerisation and main chain random scission to evolve benzenethiol and hydrogen sulfide, respectively, as major products. Depolymerisation dominated in the lower temperature pyrolysis and main chain random scission dominated in the higher temperature pyrolysis. The chain transfer of carbonisation also produced an initial pyrolysis and gradually dominated... 

A convenient method for the removal of nitrate groups from the anomeric position, e.g., those introduced by azidonitration of glycals, involving treatment with benzenethiol and ethyldiisopropylamine, has been developed. A study on denitration with hydioxylamine in pyridine established that, whereas trinitrocellulose reacts at the 2-position with high selectivity, the denitration of monomeric model compounds (tetranitrates of methyl a- and P-D-glucopyranoside, methyl a-D-mannopyranoside, methyl p-D-galactoside) takes place... 

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