Dichloroacetic Acid → Isoprene
Reaction equation
[Cl:1][CH:2]([Cl:11])[C:3]([O:5][CH2:6][CH:7]=[C:8]([CH3:10])[CH3:9])=[O:4].ClC(Cl)C(O)=O>>[CH2:6]=[CH:7][C:8](=[CH2:9])[CH3:10].[Cl:1][CH:2]([Cl:11])[C:3]([O:5][CH2:6][CH:7]=[C:8]([CH3:9])[CH3:10])=[O:4]Participants
4
Procedure
In contrast, the use of dichloroacetic acid (a liquid, bp: 194° C.; Ka =5.53×10-2) in molar excess in the above reaction results in a moderate yield (approximately 50%) of the corresponding ester (prenyl dichloroacetate, systematically named, 3-methyl-2-buten-1-yl dichloroaceate). Addition of a minor amount of an alkali-metal or alkaline-earth metallic salt or metallic salt of dichloroacetic acid (i.e., the conjugate base of dichloroacetic acid) to the reaction mixture containing dichloroacetic acid resulted in a better conversion of isoprene to prenyl dichloroacetate: 70-95% yields of the ester were obtained. This metallic salt is continuously regenerated in the reaction process.
Workup
- additionAddition of a minor amount of an alkali-metal
Sources & evidence
- ORD record
- ord-f89bbf96551243b686ffb8f05fe16204
- Source dataset
- uspto-grants-1999_02
- Patent number
- US05872277
Reaction notes
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