Disclosed are methods for preparing phenolic branched chain fatty acids or alkyl esters thereof, involving subjecting in a pressurized container (a) at least one phenolic compound, (b) unsaturated fatty acids having 6 to 25 carbon atoms, alkyl esters thereof, or mixtures thereof, and (c) H-ferrierite zeolite catalyst in the presence of distilled water or alcohol and a nitrogen atmosphere at a temperature of about 100° C. to about 400° C. and a pressure of about 10 to about 1000 psi, and isolating saturated phenolic branched chain fatty acids or alkyl esters thereof or mixtures thereof. Also disclosed are methods for killing microorganisms on or in an object, involving contacting said object with an effective microorganisms killing amount of a composition comprising phenolic branched chain fatty acids or alkyl esters thereof, and optionally a carrier; the phenolic branched chain fatty acids or alkyl esters thereof may be produced by the methods described herein.