( ( ( Another ( substitution reaction ) ) ( for benzene ) ) ( ( is sulfonation ) . ) )
(ROOT (S (NP (NP (DT Another) (NN substitution) (NN reaction)) (PP (IN for) (NP (NN benzene)))) (VP (VBZ is) (ADJP (JJ sulfonation))) (. .)))
Another substitution reaction for benzene is sulfonation.
(ROOT (S (ADVP (RB Replace)) (NP (NP (DT another)) (PP (IN in) (NP (DT a) (NN molecule)))) (VP (VBZ happens) (PP (TO to) (NP (NNS atoms))) (PP (IN during) (NP (DT a) (NN substitution) (NN reaction)))) (. .)))
Replace another in a molecule happens to atoms during a substitution reaction.