Molecular Design And Application Of Novel Surfactant Containing Carboxylmethylsulfonyl Group

In this paper, three novel anionic surfactants containing carboxylmethylsulfonyl group,which could decarboxylate at lower temperature, were synthesized and their property ofdecarboxylation at low temperature was studied. Iron oxide nanoparticles coated with andwithout surfactants were prepared and the decarboxylation of anionic surfactants on thesurface of iron oxide nanoparticles at lower temperature were also studied. Metal oxidesnanoparticles were synthesized using cetylsulfonylacetic acid and oxides modified Pd/Ccatalysts were prepared by submerging activated carbon in the tetraline solution of oxidesfollowed by refluxing and loading Pd and the synthesis of 2, 2'-dichlorohydrazobenzene byselective catalytic hydrogenation with these modified catalysts were also studied.Cetylsulfonylacetic acid, butylsulfonylacetic acid and methylene-bis-sulfonylacetic acidwere synthesized via the oxidation of sulfides. These compounds were characterized by ¹HNMR. DSC and TGA analysis, as well as thermal decarboxylation experiment, show that thedecarboxylation of carboxylmethylsulfonyl group began around 150℃and completed at210℃.Coated iron oxide nanoparticles were prepared using these three compounds by methodsof microemulsion, coprecipitation and sol-gel. Uncoated iron oxide nanoparticles could beobtained by heating in nitrogen and refluxing in tetralin to accomplish decarboxylation.Particulate structure, size, morphology and the changes of organic compounds wereCharacterized by means of XRD, TEM and FTIR. The decarboxylation of thecarboxylmethylsulfonyl group on the surface of iron oxide nanoparticles were studied byFTIR analysis of the product after decarboxylating. The results show that the decarboxylationof carboxylmethylsulfonyl group and the breaking of the bonding between this group and ironoxide could be achieved by these two methods of heating. The crystal structure of the finaliron oxide was Fe₃O₄ except the sample obtained by calcining the precipitate prepared bydecarboxylating in tetraline in method of coprecipitation of which wasγ-Fe₂O₃. All theproducts were well in nanoscale. The IR analysis of the organic compounds afterdecarboxylation indicates that the products are sulfone and hydroxide groups on the surface ofiron oxide participate in decarboxylation. Study on the synthesis of 2, 2'-dichlorohydrazobenzene by selective catalytichydrogenation of o-chloronitrobenzene over Pd/C catalysts modified with iron oxide, ceriumoxide and titanium dioxide nanoparticles show that the introduction of oxides nanoparticlescould enhance the activity and stability of Pd/C catalyst. The effect of modification withcerium oxide is best, and then iron oxide, modification with titanium dioxide is worst. XRDanalysis shows that the oxides and Pd in catalysts were amorphous before and after using.TEM analysis indicates that the oxides affected the size of Pd particles and the smaller thesize of Pd particles was, the better the catalytic activity and stability were.