Method for preparing alpha-chloro-alpha-acetyl-gamma-butyrolactone
A technology of acetyl and butyrolactone, applied in the direction of organic chemistry, etc., can solve problems such as low purity and complicated operation, and achieve the effect of simple operation and mild reaction conditions
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[0038] The preparation method of the invention can significantly improve the purity of the α-chloro-α-acetyl-γ-butyrolactone product, and slightly increase the product yield, laying a solid foundation for further preparation of high-quality VB1.
[0039] The present invention will be described in detail below by way of examples. In the following examples, all raw materials used are commercially available unless otherwise specified.
Embodiment 1
[0041] Take 273g of 15% by weight NaOH aqueous solution, stir and cool down to below 10°C, start to slowly add 128g of α-acetyl-γ-butyrolactone dropwise, cool with ice water, the reaction exotherm is obvious, control the internal temperature at 8-12°C, A large amount of solid sodium salt was precipitated in the late stage of the reaction. After the dropwise addition of α-acetyl-γ-butyrolactone, stir and keep warm for 30 minutes, then add 350g of water to dissolve the precipitate, cool the system to 8°C and slowly introduce chlorine gas to control the reaction The temperature of the liquid is 8-12°C. When the reaction liquid is finally milky white and the pH of the solution is 5.2, end the chlorine flow, nitrogen replacement, vacuum pumping for 10 minutes, let stand and separate layers, and the lower organic phase is α-chloro-α-acetyl Base-γ-butyrolactone, the gas phase content is 99.6%, and the molar yield is 97.1%.
Embodiment 2
[0043] Take 663g of 8 wt% Na 2 CO 3Stir the aqueous solution to cool down to below 20°C, start to slowly add 128g of α-acetyl-γ-butyrolactone dropwise, control the internal temperature at 18-22°C, part of the solid precipitates in the later stage of the reaction, add dropwise α-acetyl-γ-butyrolactone After the dropwise addition, stir and keep warm for 30 minutes, then add 200g of water to dissolve the precipitate, cool the system down to 10°C and slowly introduce chlorine gas, control the temperature of the reaction solution at 10-12°C, when the reaction solution finally turns milky white, the solution pH =5.8, end chlorine gas, nitrogen replacement, vacuum pumping for 10min, let stand and separate layers, the lower organic phase is α-chloro-α-acetyl-γ-butyrolactone, the gas phase content is 99.2%, and the molar yield is 96.8% .
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