Abstract: A liquid silicone rubber base is prepared by mixing an organopolysiloxane containing at least two alkenyl groups, reinforcing silica having a BET specific surface area of at least 50 m.sup.2 /g, and optionally, a mixing assistant. The mixing step includes a first stage of mixing under a first shear stress of at least 1.times.10.sup.6 N/m.sup.2 for 1-5 minutes and a second stage of mixing under a second shear stress which is up to 1/2 of the first shear stress for at least 2 minutes. The silicone rubber base is sufficiently shelf stable to minimize a viscosity rise with time.

Abstract: Silicon nitride powder is produced in two steps, by supplying metallic silicon powder to a fluidized bed composed of silicon nitride and nitrogen or ammonia gas where primary nitriding reaction is effected until the silicon powder is nitrided to an amount of at least 50% and transferring the nitrided product from the fluidized bed into a moving bed where secondary nitriding reaction is effected for nitriding the unreacted silicon with nitrogen or ammonia gas. This method is adapted for manufacture on a commercial scale because the silicon nitride powder thus obtained is consistent and has a very high degree of nitriding and a minimal variation in quality.

Abstract: Silicon nitride powder is prepared by continuously supplying metallic silicon powder to a first fluidized bed which is composed of silicon nitride powder and a non-oxidizing reaction gas containing nitrogen or ammonia gas and maintained at 1,000.degree. to 1,400.degree. C. where primary nitriding reaction takes place, and continuously withdrawing the nitride product from the first fluidized bed and supplying it to a second fluidized bed of similar composition where secondary nitriding reaction takes place for nitriding the unreacted metallic silicon powder.

Abstract: The invention provides a novel continuous process for concurrently producing methyl chloride and organosiloxanes by the reaction of an organochlorosilane and methyl alcohol in an aqueous reaction medium at 70.degree. to 150.degree. C. Different from conventional processes, the aqueous reaction medium contains no catalyst so that the problems inherent to the use of a large amount of a catalyst can be avoided. In the inventive process, the feed rates of the reactants are controlled so as to keep the concentration of hydrogen chloride in the aqueous reaction medium not to exceed the azeotropic concentration thereof at the temperature and under the pressure of operation. These conditions are critical to reduce the loss of hydrogen chloride by dissipation into the gaseous phase resulting in a remarkably high yield of methyl chloride from the standpoint of both the conversion of chlorine content and the space-time yield of the reaction vessel.