# US 10,501,567 B2 · Methods for determining transition metal compound concentrations in multicomponent liquid systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,501,567 B2 - Document ID: US10501567B2 - Status: Granted - Kind: B2 - Application number: 15/997,744 - Filed: 2018-06-05 - Published: 2019-01-24 - Granted: 2019-12-10 - Earliest claimed: 2017-07-21 - Assignees: Chevron Philips Chemical Company LP - Applicants: Chevron Phillips Chemical Company LP - Inventors: Qing Yang; Richard M. Buck - Web page: https://patentgrep.com/patent/US10501567B2 ## CPC - C08F 210/16: Copolymers of ethene with alpha-alkenes, e.g. EP rubbers - B01J 19/0006: {Controlling or regulating processes (controlling or regulating in general G05)} - G01N 21/31: Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry {(G01N21/72 takes precedence)} - G01N 21/33: using ultraviolet light (G01N21/39 takes precedence) - B01J 2219/00164: controlling the flow - C08F 4/65925: {two cyclopentadienyl rings being mutually non-bridged} - C08F 4/65927: {two cyclopentadienyl rings being mutually bridged} - C08F 10/00: Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond - G01N 2021/8416: {and process controlling, not otherwise provided for} - C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract Methods for determining the concentration of transition metal compounds in a solution containing more than one transition metal compound are described. Polymerization reactor systems providing real-time monitoring and control of the concentrations of the transition metal components of a multicomponent catalyst system are disclosed, as well as methods for operating such polymerization reactor systems. ## Claims ### Claim 1 A process for operating a polymerization reactor system, the process comprising: (I) contacting a catalyst system comprising a first transition metal compound, a second transition metal compound, an activator, and an optional co-catalyst, with an olefin monomer and an optional olefin comonomer in a reactor within the polymerization reactor system under polymerization reaction conditions to produce an olefin polymer; wherein the polymerization reactor system comprises a solution reactor, a gas-phase reactor, a slurry reactor, or a combination thereof; (II) determining a concentration of the first transition metal compound in a solution comprising the first transition metal compound and the second transition metal compound, the concentration determined via the steps of: (i) submitting a sample of the solution to a sample chamber; (ii) irradiating the sample in the chamber with a light beam at a wavelength in the UV-visible spectrum; and (iii) generating a sample absorbance profile of the sample, subtracting a reference absorbance profile of the second transition metal compound in a reference solution from the sample absorbance profile to result in a first transition metal compound absorbance profile, and correlating the first transition metal compound absorbance profile to a standard to determine the concentration of the first transition metal compound in the solution; and (III) adjusting a flow rate of the first transition metal compound into the reactor when the concentration of the first transition metal compound in the solution has reached a predetermined level. ### Claim 2 (depends on 1) The process of claim 1, wherein: the wavelength in step (ii) comprises wavelengths in the 300 nm to 600 nm range; the sample absorbance profile in step (iii) comprises an absorbance curve over a range of wavelengths; the reference solution comprises the second transition metal compound and a hydrocarbon solvent; and the step of correlating is performed at a single wavelength. ### Claim 3 (depends on 1) The process of claim 1, wherein a weight ratio of the first transition metal compound to the second transition metal compound in the solution is in a range from about 1:20 to about 1:1. ### Claim 4 (depends on 3) The process of claim 3, wherein: the catalyst system comprises a first metallocene compound, a second metallocene compound, an activator, and a co-catalyst; the catalyst system is contacted with ethylene and an olefin comonomer comprising 1-butene, 1-hexene, 1-octene, or a mixture thereof; the sample absorbance profile, the reference absorbance profile, and the first transition metal compound absorbance profile independently comprise an absorbance curve over a range of wavelengths; and the standard comprises a calibration curve. ### Claim 5 (depends on 1) The process of claim 1, wherein: the olefin polymer comprises an ethylene homopolymer and/or an ethylene ethylene/α-olefin copolymer; and at least one of the first transition metal compound and the second transition metal compound is a metallocene compound. ### Claim 6 (depends on 5) The process of claim 5, wherein: the solution comprising the first transition metal compound and the second transition metal compound is a feed stream to a catalyst preparation vessel; and the flow rate of the first transition metal compound into the reactor is controlled by adjusting a flow rate of the feed stream to the catalyst preparation vessel, and/or by adjusting a flow rate ratio of the first:second transition metal compound to the catalyst preparation vessel, and/or by adjusting a flow rate of the catalyst system exiting the catalyst preparation vessel and entering the reactor. ### Claim 7 (depends on 5) The process of claim 5, wherein: the solution comprising the first transition metal compound and the second transition metal compound is a liquid or homogeneous catalyst system; and the flow rate of the first transition metal compound into the reactor is controlled by adjusting a flow rate ratio of the first:second transition metal compound to the reactor, and/or by adjusting a flow rate of the liquid or homogeneous catalyst system entering the reactor. ### Claim 8 (depends on 5) The process of claim 5, wherein: the solution comprising the first transition metal compound and the second transition metal compound is a solution prepared from a heterogeneous or supported catalyst system; and the flow rate of the first transition metal compound into the reactor is controlled by adjusting a flow rate ratio of the first:second transition metal compound to the reactor, and/or by adjusting a flow rate of the heterogeneous or supported catalyst system entering the reactor. ### Claim 9 (depends on 5) The process of claim 5, wherein: the solution comprising the first transition metal compound and the second transition metal compound is a solution prepared from a sample mixture from the reactor; and the flow rate of the first transition metal compound into the reactor is controlled by adjusting a flow rate ratio of the first:second transition metal compound to the reactor, and/or by adjusting a flow rate of the catalyst system entering the reactor. ### Claim 10 (depends on 1) The process of claim 1, wherein: the first transition metal compound is an unbridged metallocene compound; and the second transition metal compound is a bridged metallocene compound. ### Claim 11 (depends on 1) The process of claim 1, wherein the olefin polymer comprises an oligomerization product of a C6-C24 olefin. ### Claim 12 A method for determining a concentration of a first transition metal compound in a solution comprising the first transition metal compound and a second transition metal compound, the method comprising: submitting a sample of the solution to a sample chamber comprising a flow cell; (ii) irradiating the sample in the chamber with a light beam at a wavelength in the UV-visible spectrum; and (iii) generating a sample absorbance profile of the sample, subtracting a reference absorbance profile of the second transition metal compound in a reference solution from the sample absorbance profile to result in a first transition metal compound absorbance profile, and correlating the first transition metal compound absorbance profile to a standard to determine the concentration of the first transition metal compound in the solution; wherein the solution comprises the first transition metal compound, the second transition metal compound, and a hydrocarbon solvent. ### Claim 13 (depends on 12) The method of claim 12, wherein the wavelength in step (ii) comprises wavelengths in the 300 nm to 600 nm range. ### Claim 14 (depends on 12) The method of claim 12, wherein: the sample absorbance profile, the reference absorbance profile, and the first transition metal compound absorbance profile independently comprise an absorbance curve over a range of wavelengths; and the reference solution comprises the second transition metal compound and the hydrocarbon solvent. ### Claim 15 A polymerization reactor system comprising: (A) a reactor configured to contact a catalyst system with ethylene and an optional olefin comonomer under polymerization reaction conditions to produce an ethylene polymer; (B) a catalyst preparation vessel configured to contact a first transition metal compound, a second transition metal compound, an activator, and an optional co-catalyst to form the catalyst system; (C) an analytical system configured to determine a concentration of the first transition metal compound in a solution comprising the first transition metal compound and the second transition metal compound present within the polymerization reactor system; and (D) a controller configured to control a flow rate of the first transition metal compound into the reactor based on the concentration determined by the analytical system. ### Claim 16 (depends on 15) The reactor system of claim 15, wherein the analytical system comprises an ultraviolet-visible spectrometer. ### Claim 17 (depends on 16) The reactor system of claim 16, wherein the reactor system comprises: a single loop slurry reactor; or two or more reactors, at least one of which is a loop slurry reactor. ### Claim 18 (depends on 15) The reactor system of claim 15, wherein the analytical system further comprises a filter assembly configured to filter a sample of the solution comprising the first transition metal compound and the second transition metal compound before analysis by the analytical system. ### Claim 19 (depends on 15) The reactor system of claim 15, wherein: the reactor system comprises a slurry reactor, a gas-phase reactor, a solution reactor, or a combination thereof; the ethylene polymer comprises an ethylene homopolymer, an ethylene/1-butene copolymer, an ethylene/1-hexene copolymer, or an ethylene/1-octene copolymer; and the solution comprises the first transition metal compound, the second transition metal compound, and a hydrocarbon solvent. ### Claim 20 (depends on 19) The reactor system of claim 19, wherein: the analytical system comprises an ultraviolet-visible spectrometer; and the first transition metal compound and the second transition metal compound independently comprise a bridged or unbridged metallocene compound. ### Claim 21 (depends on 15) The reactor system of claim 15, wherein: the analytical system comprises an ultraviolet-visible spectrometer with an integrated computer system for measuring a sample absorbance profile of the first transition metal compound in the solution, for subtracting a reference absorbance profile of the second transition metal compound in a reference solution from the sample absorbance profile to result in a first transition metal compound absorbance profile, and for correlating the first transition metal compound absorbance profile to a standard to determine the concentration of the first transition metal compound in the solution; the solution comprises the first transition metal compound, the second transition metal compound, and a hydrocarbon solvent; and the solution is a feed stream to the catalyst preparation vessel, and the controller controls the flow rate of the first transition metal compound into the reactor by adjusting a flow rate ratio of the first:second transition metal compound to the catalyst preparation vessel.