Low molecular weight polydimethylsiloxanes containing high concentration of alkali was prepared by heating potassium hydroxide with octamethylcyclotetrasiloxane

KOH+n(CH3)2SiO]4一KO[(CH3)2Si十OH．When this mixture was heated，either in N2 or in O2，the amount of insoluble gel formed was the same．Methane was the sole gas evolved in this reaction，indicating that Si—CH3 is attacked by KOH，forming CH4 and Si-OK，which，through hydydo-lysis and condensation．forms Si—O—Si linkage．The rate of methane evolution at 150°using 2.3 to 4.8％ of KOH in polydimethylsiloxane is shown in Figs．1 and 2，Fig．3 gives the rate at various temperatures using 3％ KOH．