Abstract: A method is disclosed for promoting isomerization of sym-octahydrophenanthrene (s-OHP) to sym-octahydroanthracene (s-OHA) in the presence of a catalyst provided by aluminum chloride or aluminum bromide, or a mixture of these two compounds. The rate of isomerization is increased by having the reaction run in the presence of an aralkyl halide such as benzyl chloride.

Abstract: A method is disclosed for promoting isomerization of sym-octahydrophenanthrene (s-OHP) to sym-octahydroanthracene (s-OHA) in the presence of a catalyst provided by aluminum chloride or aluminum bromide, or a mixture of these two compounds. The rate of isomerization is increased by having the reaction run in the presence of an aroyl halide, such as benzoyl chloride or isophthaloyl chloride.

Abstract: A method is disclosed for promoting isomerization of sym-octahydrophenanthrene (s-OHP) to sym-octahydroanthracene (s-OHA) in the presence of a catalyst provided by aluminum chloride or aluminum bromide, or a mixture of these two compounds. The rate of isomerization is increased by having the reaction run in the presence of an acyl peroxide such as benzoyl peroxide or lauroyl peroxide.

Abstract: A method is disclosed for promoting isomerization of sym-octahydrophenanthrene (s-OHP) to sym-octahydroanthracene (s-OHA) in the presence of a catalyst provided by aluminum chloride or aluminum bromide, or a mixture of these two compounds. The rate of isomerization is increased by having the reaction run in the presence of an aryl phenone such as benzophenone.

Abstract: A method is disclosed for extracting sym-octahydroanthracene (s-OHA) from a product isomer mixture formed by the aluminum chloride catalyzed isomerization of sym-octahydrophenanthrene (s-OHP). Isolation of the s-OHA product isomer is accomplished by contacting the reaction product mixture with a specified liquid hydrocarbon solvent into which the s-OHA product isomer and unconverted s-OHP isomer dissolve and separate from a residue. The undissolved residue comprises a complex made up of aluminum chloride catalyst and small amounts of the s-OHA and s-OHP isomers. This catalyst complex may be recycled into a fresh starting mixture of s-OHP isomer for catalysis of a subsequent s-OHP isomerization reaction.

Abstract: Thermoset epoxy foams are produced from an epoxy resin, delta-1-tetrahydrophthalic anhydride, and an amine accelerator. These compounds are mixed in resin-foaming amounts to produce a foamable mixture to which typical foam additives like auxiliary blowing agents, surfactants, microscopic spheres, etc., may also be added. This foamable mixture is heated at a temperature of at least 115.degree. C. to foam and cure the mixture to produce thermoset epoxy foams.

Abstract: The delta-4 isomer of tetrahydrophthalic anhydride is isomerized in the presence of a catalytic amount of palladium and selected acid anhydrides that liquify the normally solid delta-4 isomer at a temperature below its melting point. This permits the isomerization to be effected at relatively low temperatures and in relatively short times to produce a mixture of isomers of tetrahydrophthalic anhydride that is in the liquid state at temperatures in the range of room temperature.