A Study On Synthesis Of 2,5-dimethyl-4-hydroxy-3(2H)-furanone

2,5-Dimethyl-4-hydroxy-3(2H)-furanone which is called pineapple ketone is a safe food additive permitted by FEMA and COE. It is widely used as a perfume in food, beverage, ice-cream and cigarette products,and has a powerful caramel-like odour and weak broad bean flower smell.It is widespread but rare existing in nature. The used furanone is gained by chemical synthesis. There are many kinds of synthetic methods for furano ne. A review about present research and application of furanone was give n,and the various synthetic methods were discussed in this paper.Finally, the optimum synthetic route was suggested.In the dissertation, the synthetic route using ethyl lactate and 2-halo-propionate as raw materials to prepare furaneol was selected, and the title compound was gained with high yield. The major works are as follows: 1) Preparation of ethyl 2-bromopropionate. Propionic acid was brom-inated with PC1₃ as catalyst, and then the synthetic product was esterified with p-toluene sulfonic acid as catalyst and benzene as water-carrying age -nt. The purified product was analyzed by GC, MS. Its purity was 98.7% and the yield was 94.7%. The structures of the compounds were confirmed by MS and IR. The route of reaction is as follow:2) Synthesis of 2-chloropropionate. Ethyl lactate was chlorinated by thionyl chloride and pyridine. The effect of reaction conditions such as ratio of material, reaction time, and temperature were investigated. After purification, the title compound was analyzed by GC and GC-MS, and...