A method of forming a heterogeneous protective layer on a surface of a component in a reactor is useful for repair and/or protection. The reactor may be used for production of polycrystalline silicon or a reactant thereof. The heterogeneous protective layer comprises silicon, and may comprise silicon carbide (SiC) and/or silicon nitride (Si.sub.3N.sub.4). The method comprises providing a polymeric composition for forming the heterogeneous protective layer. The polymeric composition may comprise a polycarbosilane and/or a polysilazane. The method further comprises providing the component. The surface of the component comprises carbon, such as graphite, carbon fiber reinforced carbon, or a combination thereof. The method further comprises applying the polymeric composition on the surface to form a pre-cured coating layer. The method further comprises heating the pre-cured coating layer to form the heterogeneous protective layer. The surface of the component is present within the reactor during heating of the pre-cured coating layer.

A reactor for carrying out a chemical reaction has a reactor vessel, one or more reaction tubes and means for the electrical heating of the one or more reaction tubes. The reactor vessel has one or more discharge orifices which are permanently open or are set up to open above a preset pressure level, and gas feed means are provided, which are set up to feed an inerting gas into an interior of the reactor vessel.

The present specification relates to a method comprising: (A) mixing a ferrite-based catalyst molded article with diluent material particles; and (B) adding the mixture to a catalyst reactor, and a method for preparing butadiene using the same.