METHOD OF DETERMINING CONCENTRATION OF A TRANSITION METAL COMPOUND IN A MULTICOMPONENT LIQUID SYSTEM Russian patent published in 2022 - IPC C08F2/00 C08F2/01 C08F210/16 G01N21/31 G05D11/13 

FIELD: measurement technology; chemistry.

SUBSTANCE: invention relates to a method of determining concentrations of transition metal compounds in solutions containing more than one transition metal compound. Method includes: (I) contacting a catalyst system comprising a first transition metal compound, a second transition metal compound, an activator and an optional cocatalyst, with an olefin monomer and an optional olefin comonomer in a reactor within a polymerisation reactor system under polymerisation reaction conditions to produce an olefin polymer; (II) determining a first concentration of a first transition metal compound and a second concentration of a second transition metal compound in the solution, containing a first transition metal compound and a second transition metal compound, wherein the first concentration and the second concentration are determined at steps including: (i) obtaining a first reference absorption profile (F₁) of a first transition metal compound in a first reference solution at a first known concentration and a second reference absorption profile (F₂) of a second transition metal compound in a second reference solution at a second known concentration; (ii) feeding a sample of the solution into a sample chamber; (iii) irradiating the sample in the chamber with a light beam at a wavelength in the UV-visible spectrum; (iv) generating an absorption profile of the sample and calculating a curve having formula β₁F₁ + β₂F₂, to match the absorption profile of the sample to a least square regression value (R²) of at least 0.9; where: β₁ is the first weight coefficient; F₁ is the first reference absorption profile of the first transition metal compound in the first reference solution at a first known concentration; β₂ is the second weight coefficient; and F₂ is a second reference absorption profile of a second transition metal compound in a second reference solution at a second known concentration; and (v) multiplying the first known concentration by β₁ to determine the first concentration of the first transition metal compound in the solution, and multiplying the second known concentration by β₂ to determine the second concentration of the second transition metal compound in the solution; and (III) controlling the first flow rate of the first transition metal compound and/or the second flow rate of the second transition metal compound into the reactor when the first concentration and/or second concentration have reached a predetermined level.

EFFECT: proposed method enables to improve the accuracy of measuring the amount of transition metal compounds present in the catalyst component feed streams, catalyst systems and polymerisation reactor systems, which leads to improved quality control and consistency of the polymerisation process.

11 cl, 20 dwg, 8 ex