Reactions of benzene ring: · Part 3

with acidic solution of sodium dichromate? . when phenol is treated with propan- -ol in the presence of HF, Friedel-Craft reaction takes place . Identify the products. Ethers: Ethers are a class of organic compound in which an oxygen atom is connected to two alkyl/aryl groups ( R - O - R ) . Ethers can be considered as the derivatives of hydrocarbon in which one hydrogen atom is replaced by an alkoxy ( -OR ) or an aryloxy( -OAr ) group. The general formula of aliphatic ether is C H n 2n+ Classification: Ethers Simple ethers Mixed ethers (both alkyl or aryl groups attached to oxygen atom are same (Two alkyl or aryl groups attached to oxygen atom are different) Aliphatic ethers (Two alkyl groups are attached to etherial oxygen Aromatic ethers Any one (or both ) the group attached to the etherial oxygen is aryl group CH methoxy methane -methoxy propane phenoxy benzene methoxy benzene of XII U11-Hydroxy XII U11-Hydroxy - - - - Structure of functional group The structure of ethereal oxygen which is attached to two alkyl groups is similar to the structure of -O-H group of alcohol. The oxygen atom is sp hybridized. Two sp hybridized orbitals of oxygen linearly overlap with two sp hybrid orbitals of the carbon which are directly attached to the oxygen forming two C-O ' σ ' bonds. The C-O-C bond angle is slightly greater than the tetrahedral bond angle due to the repulsive interaction between the two bulkier alkyl groups. IUPAC System: Let us recall the naming of ethers according to IUPAC nomenclature. Compound (Common Name, Structural formula, IUPAC Name) IUPAC Name Prefix with position number Root used Primary suffix Secondary Suffix Dimethyl ether Methoxymethane Methoxy Meth ane – Isopropyl methyl ether CH -methoxypropane -methoxy prop ane – t-butylmethyl ether -methoxy- -methyl propane -methoxy -methyl prop ane – Methylphenylether(Anisole) C H Methoxybenzene Methoxy benzene – – Ethylphenylether(phenetole) C H CH CH Ethoxybenzene Ethoxy benzene – – Diphenylether or phenylether C H C H