A process for improving the thermal oxidative degradation and simultaneous purification of linear polyolefines

    公开(公告)号:GB896306A

    公开(公告)日:1962-05-16

    申请号:GB3762260

    申请日:1960-11-02

    Applicant: BASF AG

    Abstract: In an improvement in the process of the parent Specification for the thermal oxidative degradation and simultaneous purification of linear polyolefins prepared by polymerization of olefins containing 2 to 4 carbon atoms with catalysts containing heavy metals of Group IVa, Va or VIa of the Mendeleeff Periodic Table and which contain small amounts of these catalysts, which comprises dissolving the polyolefin in an inert organic solvent and heating the solution in the presence of oxygen or oxygen supplying compounds for 15 to 200 minutes at 70 DEG to 240 DEG C., the solution of the polyolefin is prepared from a suspension of the polyolefin in the solvent by leading in superheated steam. The superheated steam may be under a pressure of 5 to 100 atmospheres, and basic compounds such as ammonia or alkylamines, air or oxygen may be metered into the steam. In an example a solution of polypropylene is prepared from a suspension thereof in heptane by leading in steam at 14 atmospheres into which ammonia and air have been metered.

    A process for the thermal oxidative degradation and simultaneous purification of linear polyolefines

    公开(公告)号:GB883804A

    公开(公告)日:1961-12-06

    申请号:GB2642660

    申请日:1960-07-29

    Applicant: BASF AG

    Abstract: Linear polyolefines which have been prepared by the polymerization of olefines containing two to four carbon atoms using as catalysts heavy metals of Group IV(a), V(a), or VI(a) of the Mendelleeff Periodic System are simultaneously purified and thermally degraded by dissolving or swelling the polyolefine in an inert organic solvent and heating the solution in the presence of oxygen or oxygen-supplying compounds for 15 to 200 minutes at a temperature between 70 DEG and 240 DEG C. Optionally the heat-treatment may be effected in the presence of 2 to 20% of water and in the presence of such an amount of an alkaline compound that the pH in the aqueous solution after the heat-treatment step is 6 to 7. Substances which have a large internal surface on to which impurities are absorbed may be added to the polymers before, during, or after the heat-treatment. Suitable substances are carbon, aluminium oxide, bleaching earths, and kieselguhr. The linear polymers may be polyethylene, polypropylene, or copolymers of ethylene and/or propylene and/or butene-1. Specified solvents are tetra- or decahydro-naphthalene, cyclohexane, benzene, toluene, xylene, and ethylbenzene. The oxygen-supplying compounds may be peroxides. Alkaline compounds which may be included in the heat-treatment step are ammonia, sodium, potassium, or calcium hydroxide, hydroxylamine or aniline.

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