Reagents and Conditions for Organic Chemistry
ions Reagent/ Condition; Reaction | Explanation | Oxygen supply; Combustion | Limited supply of oxygen: CO formed.Even less Oxygen: C is deposited as soot. Excess Oxygen: Complete combustion (giving CO2 and H2O) | Al2 O3 and vaporisation of alkane at 500°C; Cracking of Alkanes | Al2 O3 is used as a catalyst. Heat provides energy for breakage of C-C bonds. | UV light; Initiation step of FRS of alkanes by halogens * Not required for electrophilic addition reaction btw Halogens and alkenes | Br-Br 2Br Provides the energy for homolytic fission of Br-Br bond. Visible and infra-red radiations are unable to break covalent bonds while UV light can, because one quantum of UV light has sufficient energy (396 kJmol-1) to break the typical covalent bond (with BE of about 300 kJmol-1) while the other two do not. | Platinum Catalyst; Reforming of straight chain Alkanes | Used as catalyst. Benzene can be formed from the reforming of hexane. | Aqueous Br2 vs. Br2/NaCl; Electrophilic Addition reaction btw Halogens and Alkenes | Aq Br2 bromoalcohol formed: Br- & OH- are present in solution when carbocation is formed.Br2/NaCl bromochloro formed: Br- & Cl- are present in solution when carbocation is formed | High Temp and High Pressure vs. Milder Conditions + Ziegler-Natta catalysts; Formation of Polyethene | High Temp and High Pressure Low Density Polyethene formed Milder Conditions + Ziegler-Natta catalysts High density Polyethene formedZiegler-Natta catalyst: Al(C2H5)3/TiCl4 | Excess con H2SO4 at 440K or vaporised alcohol passed over Al2O3 catalyst; Dehydration of alcohols | -OH group and H from adjacent C atom removed alkene formed with C=C bond at the position where H and OH were removed | Refluxing | A water cooled Liebig condenser is fitted vertically to the reaction flask. Vapours that escape from the reaction mixture condense on the walls of the condenser and drip back into the flask. Top of condenser must not be stoppered. prevents vapours from