Лена CH3-CH2-CH2-OH+PCl5=CH3-CH2-CH2-Cl+POCl3+HCl CH3-CH2-CH2Cl+KOH->CH3-CH=CH2+H2O+KCl CH3-CH=CH2+Br2->CH3-CHBr-CH2Br CH3-CHBr-CH2Br+2KOH=CH3-C---CH+2KBr+2H2O пропин