CONTINUOUS METHOD FOR SEPARATING SALTS IN THE PRODUCTION OF DIMETHYLACETAMIDE

    公开(公告)号:US20150329477A1

    公开(公告)日:2015-11-19

    申请号:US14653094

    申请日:2013-12-18

    申请人: BASF SE

    IPC分类号: C07C231/24 B01D3/42 B01D3/06

    摘要: What is proposed is a continuous process for discharging a solid, salt-containing phase comprising alkali metal acetates and/or alkaline earth metal acetates from the product mixture from the preparation of N,N-dimethylacetamide (DMAC) by reaction of methyl acetate (MeOAc) with dimethylamine (DMA) in the presence of a catalyst comprising N,N-dimethylacetamide (DMAC), methyl acetate (MeOAc), dimethylamine (DMA) and a catalyst, having the following process steps: level-regulated feeding of the product mixture as feed stream into an evaporation vessel of a forced circulation evaporator, flash evaporation of volatile components of the product mixture in the forced circulation evaporator to form a vapor phase comprising N,N-dimethylacetamide (DMAC) and precipitation of a solid, salt-containing phase comprising alkali metal acetates and/or alkaline earth metal acetates, recycling of the volatile components of the product mixture obtained after the flash evaporation, removal of a vapor phase comprising N,N-dimethylacetamide (DMAC) from the evaporation vessel as output stream, concentration of the solid, salt-containing phase comprising alkali metal acetates and/or alkaline earth metal acetates in the forced circulation evaporation circuit of the forced circulation evaporator, discharge of a substream comprising the solid, salt-containing phase comprising alkali metal acetates and/or alkaline earth metal acetates from the forced circulation evaporation circuit of the forced circulation evaporator, solid/liquid separation of the discharged substream in at least one separation apparatus into a solid, salt-containing phase comprising alkali metal acetates and/or alkaline earth metal acetates and a liquid phase, recycling of the liquid phase obtained after the solid/liquid separation into the forced circulation evaporation circuit as recycle stream, wherein the recycling of the volatile components of the product mixture obtained after the flash evaporation and of the solid, salt-containing phase comprising alkali metal acetates and/or alkaline earth metal acetates into the evaporation vessel is effected via an introduction section which ends within a range from 30 cm above the level surface to 20 cm below the level surface of the fill level of the evaporation vessel.