Process for preparing diisopropenyldiphenyl and homologs thereof

The Specification comprises compounds having the formula: where n is an integer; these and p,p1-di-isopropenyldiphenyl are prepared by heating a solution of a compound of the formula: where n is O or an integer, in an inert, highboiling, non peroxide-forming solvent, distilling off a major portion of the solvent-water mixture formed by dehydration, slowly adding preheated anhydrous ethylene glycol whilst distilling off the remainder of the solvent, slowly adding more preheated ethylene glycol while distilling off ethylene glycol containing the desired product. The inert solvent is preferably a hydrocarbon mixture such as "Shell" (Registered Trade Mark) 140 (boiling range 185-212 DEG C.) or "Kensol" 48 and should be immiscible with water and ethylene glycol and form azeotropic mixtures with them and have a boiling point high enough to bring about melting and dehydration of the carbinol. The ethylene glycol preferably contains a polyalcohol, e.g. mannitol, or a heat-stable, anhydrous, inorganic salt soluble in ethylene glycol, e.g. lithium chloride, potassium chloride or calcium chloride. A polymerisation inhibitor, e.g. 2,6-di-tert.-butyl-para-cresol, is preferably present during the process.