4-Chloro-2-cyclopentylphenol is prepared by shaking 4-chlorophenol and cyclopentene in concentrated sulfuric acid; 2,6- dicyclopentyl-4-chlorophenol (bp 235–240 ℃ at 1.8 kPa) is produced as a byproduct. 4-Chloro-2- cyclopentylphenol is no longer used as a microbicide in disinfectants because of its toxicity.
LD50 (oral, rat) 2460 mg/kg, LD50 (oral, rabbit) 420 mg/kg, LD50 (dermal, rabbit) 850 mg/kg. 4-Chloro-2- cyclopentylphenol strongly irritates the skin and mucous membranes but is not sensitizing.
