| 摘要 |
There is provided a process for the preparation of 4-hydroxy-6-methyl-2-pyrone which comprises reacting dehydroactate acid (DHAA) with aqueous H2SO4 containing 90-99% by weight of H2SO4 at a temperature from 60 DEG C to 140 DEG C and under a pressure of 10 millimetres of mercury gauge to 388 centimetres of mercury gauge, wherein (A) the H2SO4 plus H2O: DHAA weight ratio is from 0.8 to 3:1 and (B) the DHAA is initially reacted with from 91 to 99% H2SO4 followed by one or more staged H2O additions during the reaction whereby the total weight of H2O added and initially present in the H2SO4 charged is 10% or less of the weight of H2SO4 (100% basis) initially charged, said staged H2O addition(s) being optional when 93-96% H2SO4 is initially charged. |
