Study On Synthesis And Technology Of2-phenylpropionaldehyde Compounds

2-Phenylpropionaldehydes are important synthetic perfumes and chemical intermediates widely used in the synthesis of dyestuffs,pharmaceuticals and pesticides. In this dissertation,2-phenylpropionaldehyde compounds were effectively prepared involving saponification, neutralization and decarboxylation rearrangement etc. unit processes via the ethyl β-phenylepoxy butyrate and β-(4-methoxyphenyl)epoxy butyrate precursors formed by Darzens reaction of acetophenone and4-methoxyacetophenone respectively with ethyl chloroacetate in the presence of base. Some technological parameters for the synthetic processes were discussed and optimized in details.Various basic condensing agents such as potassium tert-butoxide, sodium amide, sodium alcoholate were employed for catalytically synthesizing ethyl β-phenylepoxy butyrate by Darzens reaction with acetophenone as the substrate. It was observed that87.6%yield was obtained when the reaction was conducted at30℃for6h in the presence of sodium amide/potassium tert-butoxide in89.8%conversion of acetophenone. Similarly ethyl β-(4-methoxyphenyl)epoxy butyrate of64.2%yield in65.8%substrate conversion was achieved by Darzens reaction.Some reaction conditions were selected to saponification process of ethy1β-phenylepoxy butyrate compounds. It was found that the reaction conducted at50℃for4h to form respectively88.6%yield of sodium β-phenylepoxy butyrate and76.9%yield of sodium β-(4-methoxyphenyl)epoxy butyrate in the presence of25%sodium hydroxide under ethanol medium.Reaction temperature and acidity were discussed in the neutralization and decarboxylation processes of sodium β-phenylepoxy butyrate compounds. The92.9%yield of2-phenylpropionaldehyde and94.6%yield of2-(4-methoxyphenyl)propionaldehyde were respectively achieved by refluxing the mixture of sodium β-phenylepoxy butyrate at70℃for4h under pH=2acidic atmosphere.