PART-STREAM DISTILLATION Russian patent published in 2018 - IPC C07D301/12 C07D301/32 B01D3/14 

FIELD: chemistry.

SUBSTANCE: present invention relates to a continuous process for the production of propylene oxide, which comprises: (a) reacting propene, optionally mixed with propane, with hydrogen peroxide in a reaction apparatus in the presence of acetonitrile as solvent to produce stream S0 at the outlet of the reaction apparatus, wherein S0 contains propylene oxide, acetonitrile, water, at least one additional component B, optionally propene and optionally propane, and is characterised in that the normal boiling point of at least one component B is higher than the normal boiling point of acetonitrile, and is characterised in that the decadic logarithm of the octanol-water partition coefficient (log K_ow) of at least one component B is greater than zero; (b) separating the propylene oxide from S0, optionally after separation of propene and optionally propane, to obtain stream S1 which contains acetonitrile, water, and at least one additional component B; (c) dividing S1 into two streams S2 and S3, wherein the total mass of S3 with respect to the total mass of S1 is in the range of 0.01 to 25%; (d) subjecting stream S3 to vapour and liquid phase fractionation in a fractionation unit to produce a stream of vapour fraction S4 depleted of at least one component B, and to obtain liquid bottom stream S4b depleted of acetonitrile; (e) recycling at least a portion of stream S4, optionally after treatment, to step (a) and recycling at least a portion of stream S2, optionally after treatment, to step (a).

EFFECT: technical result is the creation of a cost-effective continuous process for the production of propylene oxide in acetonitrile as a solvent, which avoids the accumulation of impurities in the recirculating solvent stream of acetonitrile.

19 cl, 1 dwg, 13 tbl, 19 ex