trans-2,4-Difluorocinnamic acidtrans-2,4-Difluorocinnamic acid反式-2,4-二氟肉桂酸3-(2,4-Difluorophenyl)acrylic acid2,4-Difluorocinnamic acid3-(2,4-Difluorophenyl)prop-2-enoic acidtrans-2,4-Difluorocinnamic acid 98%(2E)-3-(2,4-Difluorophenyl)prop-2-enoic acid(E)-3-(2,4-Difluorophenyl)acrylic acid(E)-3-(2,4-Difluorophenyl)acrylic acid3-(2,4-Difluorophenyl)acrylic acid