METHOD FOR OBTAINING SPIRO[2.4]HEPTA-4,6-DIENE Russian patent published in 2018 - IPC C07C13/72 C07C2/86 

FIELD: technological processes.

SUBSTANCE: method is proposed for the preparation of spiro[2.4]hepta-4,6-diene, which consists in preheating to boiling (40–45 °C) mixtures of 1,2-dichloroethane with cyclopentadiene are added 50 % wt. aqueous NaOH solution in the presence of a phase transfer catalyst and the process is carried out at a molar ratio of cyclopentadiene : 1,2-dichloroethane : catalyst : NaOH = 1 : 1 : 0.001–0.01 : 2.5–6 followed by isolation of the desired product from the reaction mixture by steam distillation. Process is carried out in a single reactor and the yield of the desired product is 75–90 %.

EFFECT: increase the yield of the target product (75–90 %), as well as simplify the process technology by conducting all the stages in one reactor without the use of vacuum distillation and organic solvents, which increases its environmental friendliness.

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