FIELD: organic chemistry, chemical technology. SUBSTANCE: invention relates to methods for preparing and purification of 3,3-dimethylbutyraldehyde. The first method involves contact of 1-chloro-3,3- dimethylbutane and dimethylsulfoxide in the presence of inorganic bromide taken in the amount 0.05-10 eqv or inorganic iodide taken in the amount 0.01-1.5 eqv and in the presence of a base taken in the amount 1-10 eqv. The second method involves contact of tert. -butyl chloride and ethylene in the presence of aluminum chloride to yield 1-chloro- 3,3-dimethylbutane, isolation of 1-chloro-3,3-dimethylbutane followed by contact of 1- chloro-3,3-dimethylbutane with dimethylsulfoxide to form 3,3-dimethylbutyraldehyde under conditions of the first method. The end product prepared by the first and the second methods is purified by its treatment with sodium bisulfite an aqueous solution with solvent not mixing with water, washing out and contact at heating with aqueous organic base or aqueous inorganic acid followed, if necessary, by distillation off. Method allow preparing 3,3- -dimethylbutyraldehyde by reproducible and highly economic manner and with high purity. EFFECT: improved methods for synthesis and purification. 18 cl, 5 ex
