METHOD FOR PURIFICATION OF AN AROMATIC DIACID OR THE CORRESPONDING ANHYDRIDE
申请人:SABIC Global Technologies B.V.
公开号:US20180079705A1
公开(公告)日:2018-03-22
A method of purifying a stream having an aromatic carboxy-aldehyde and an aromatic acid or the corresponding anhydride is described. The method includes reacting a hydroxylamine-containing compound with the aromatic carboxy-aldehyde in the stream to form a reaction mixture including the corresponding nitrone; adding an aqueous solvent to the reaction mixture, in an amount and under conditions effective to solubilize the nitrone but not the organic acid or the corresponding anhydride; and separating the solubilized nitrone from the non-solubilized organic acid. The nitrone is a water soluble nitrone.
A method of preventing polymer scales from sticking in a polymerization vessel during the polymerization of a monomer having an ethylenically double bond, wherein said polymerization is carried out in a polymerization vessel of which the inner wall and other parts with which said monomer comes into contact during polymerization are previously first coated with (a) a coating solution comprising a cationic dye and the resulting coating is then coated with (b) a coating solution comprising at least one component selected from the group consisting of anionic polymeric compounds, amphoteric polymeric compounds and hydroxyl group-containing organic compounds. Polymer scale formation can be effectively prevented.