ChemInform Abstract: THERMISCHE UMLAGERUNG PHENYLHALTIGER SILOXANE IN GEGENWART ALKALISCHER KATALYSATOREN

Abstract

Die thermische Umlagerung der Methylphenylsiloxane (I) in Gegenwart von LiOH, KOH oder NaOH bei Temperaturen zwischen 240 ‐ 320°C wird untersucht.

Methods of Synthesis of αω-Difunctional Oligosiloxanes with Two Organic Substituents Per Unit

“…This is because the rate of cleavage of 1,3,5,7-tetramethyl-l,3,5,7-tetraphenylcyclotetrasiloxane is comparable to the rates of the secondary processes (reactions of the alcohol with the alkoxysiloxanes) 87 . However, the effect of ring size is somewhat reduced when sodium methoxide is employed as a catalyst 86 .…”

“…When 1,3,5-trimethyl-l ,3,5-triphenylcyclotrisiloxane is heated with alcohols in the presence of hydrochloric acid or KIL activated clay, 1,5-dialkoxymethylphenylsiloxanes RO[CH 3 (C 6 H 5 )SiO] 3 R (R = C 2 H 5 , n-CaH,, or iso-CaH,) are formed in yields up to 72-86% 87 . Hydrochloric acid, perchloric acid, or an aluminosilicate may be employed as catalysts 88 .…”

“…Hydrochloric acid, perchloric acid, or an aluminosilicate may be employed as catalysts 88 . The reaction is significantly influenced by the size of the cyclosiloxane ring, the nature of the substituents at the silicon atoms, and the catalyst.…”