A new class of solid-liquid phase-transfer catalysts has been prepared. These tris(polyoxaalkyl)amines (I) are designed to obtain the best balance between straightforward synthesis (cheap starting materials), high activity, easy recovery, and low toxicity. The catalysts are synthesized from ethylene glycols by a simple one-step method in yields in the range of 65-81 %. They show high catalytic effects in aliphatic nucleophic substitutions and aromatic nucleophilic substitutions on activated and unactivated molecules. In the Ullman synthesis (a new PTC reaction) there is a synergic effect of anionic activation by tridents and by copper salts. Reactions have been carried out at temperatures up to 180 °C without evidence of decomposition of the tris(polyoxaalkyl)amines. The behavior and catalytic activity of these catalysts are discussed.

No abstract

No abstract

Polymethylsilane (PMS) with a general formula SiH) 1-y -(CH 3 Si) y -] n has been synthesized by Wu ¨rtz type polycondensation of methyldichlorosilane. Copolycondensation with dimethylchlorosilane was realized in an attempt to control the viscosity of the PMS. Thermal reactions at 230 °C with small amounts (1 wt %) of boron derivatives such as B[OSi-(CH 3 ) 3 ] 3 serve to cross-link this Si-H-containing organosilicon polymer. As a result, when the products of these reactions are pyrolyzed at 1000 °C under argon, the ceramic residue yields are increased considerably over those obtained with the original polymers.