Production of benzotriazoles
    6.
    发明授权
    Production of benzotriazoles 失效
    苯并噻唑的生产

    公开(公告)号:US3639431A

    公开(公告)日:1972-02-01

    申请号:US3639431D

    申请日:1968-05-24

    CPC分类号: C07D249/18

    摘要: IN A PROCESS FOR RECOVERING BENZOTRIAZOLE THAT IS PRODUCED BY REACTING AN ORTHO-PHENYLENEDIAMINE WITH NITROUS ACID IN AQUEOUS MEDIA, THE IMPROVEMENT WHICH COMPRISES ADDING A POLYHYDROXY COMPOUND TO CRUDE BENZOTRIAZOLE SEPARATED FROM THE AQUEOUS PHASE OF THE PRODUCT MIXTURE AND CODISTILLING THE BENZOTRIAZOLE AND THE POLYHYDROXY COMPOUND, THEREBY INCREASING THE YIELD AND LESSENING THE DANGER OF EXPLOSIVE DECOMPOSITION OF THE BENZOTRIAZOLE DURING DISTILLATION. IN A PREFERRED EMBODIMENT OF THE IMPROVEMENT A SUBSTANTIALLY WATER-INSOLUBLE ALKANOL IS INITIALLY ADDED TO THE AQUEOUS PRODUCT MEXTURE CONTAINING THE BENZOTRIAZOLE IN ORDER TO FACILITATE THE SEPARATION OF THE BENZOTRIAZOLE FROM THE AQUEOUS LAYER OF THE PRODUCT MIXTURE.