Process and catalyst composition for preparing organosilicon compounds via isomerization and hydrosilylation of internal olefins

Abstract

A method for manufacturing an organosilicon compound is provided. The process includes isomerization and hydrosilylation starting from an internal olefin compound and a silyl hydride compound. A catalyst composition comprising a platinum hydrosilylation reaction catalyst and an iridium (I)-ligand complex is capable of catalyzing isomerization and hydrosilylation reactions.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application Serial No. 63 / 451,935, filed on March 14, 2023. U.S. Provisional Patent Application Serial No. 63 / 451,935 is incorporated herein by reference. Technical Field

[0003] Disclosed are methods and catalyst compositions for preparing organosilicon compounds. More specifically, the methods include isomerizing an internal olefin compound to form a terminal olefin compound, and hydrosilylating the terminal olefin compound to form a reaction product comprising the organosilicon compound. Background Art

[0004] Typical industrial hydrosilylation catalysts, such as Speier's catalyst and Karstedt's catalyst, are generally known to hydrosilylate terminal olefins, but are significantly less reactive in hydrosilylating internal olefins. When hydrosilylating a mixture of terminal and internal olefins, unreacted internal olefins may be disposed of, resulting in low feedstock efficiency. In some cases, high catalyst loadings and high reaction temperatures can be used to react internal olefins to alleviate this difficulty, but high catalyst loadings are not cost-effective, higher temperatures result in more power consumption, which reduces cost effectiveness, and high catalyst loadings and high temperatures can lead to excessive side reactions, which reduce quality and yield.

[0005] The steric aspect of the internal double bond and other factors influence the hydrosilylation reaction. Using Custer's catalyst, the hydrosilylation of oct-1-ene with trichlorosilane is quite rapid, but significant isomerization of the double bond occurs, and significant formation of the corresponding oct-2-ene occurs. See, for example, Meister et al., "Platinum Catalysis Revisited—Unraveling Principles of Catalytic Olefin Hydrosilylation," ACS Catal. 2016, 6, 1274-1284.

[0006] There is an industrial need to provide organosilicon compounds via hydrosilylation in a process with high yield and selectivity. Summary of the Invention

[0007] The catalyst composition comprises at least 0.5 ppm of a platinum hydrosilylation catalyst and at least 50 ppm of an iridium (I) complex. The catalyst composition can be used to catalyze isomerization and hydrosilylation reactions. The catalyst composition can be used in a method for preparing an organosilicon compound, wherein the method comprises:

[0008] 1) Mixing starting materials, which include

[0009] A) an olefin component comprising A-1) an internal olefin compound, wherein the internal olefin compound is linear or branched, has at least 4 carbon atoms per molecule, and has at least one internal double bond per molecule;

[0010] B) a silyl hydride compound having at least one silicon-bonded hydrogen atom per molecule; and

[0011] C) Catalyst composition. DETAILED DESCRIPTION

[0012] The starting materials A) olefin component, B) silyl hydride compound, C) catalyst composition and optionally D) solvent can be used in the process described above. These starting materials are described in detail below.

[0013] A) Olefin components

[0014] The starting material A) in the methods described herein is an olefin component. The olefin component comprises A-1) an internal olefin compound, wherein the internal olefin compound is linear or branched, has at least 4 carbon atoms per molecule, and has at least one internal double bond per molecule. The internal olefin compound can be an internal olefin. For example, the internal olefin can have the formula A-1-1): where R 2 With empirical formula -C p H (2p+1) , where subscript p≥1; R 4 With empirical formula -C q H (2q+1) , where subscript q≥1; R 8 With empirical formula -C r H (2r+1) , where subscript r≥0; and R 10 With empirical formula -C s H (2s+1) , where subscript s≥0. R 2 and R 4 Each of R may independently be linear or branched. 8 and R 10 Each of may be H (eg, when r and / or s = 0). Alternatively, R 8 and R10 Each of may independently be linear or branched (i.e., when r and / or s is 2 or greater). Alternatively, subscript p may be from 1 to 8. Alternatively, subscript q may be from 1 to 8. Alternatively, subscript r may be from 1 to 8. Alternatively, subscript s may be from 1 to 8. Alternatively, the amount (p+q+r+s) may be from 2 to 14, alternatively from 2 to 6. Examples of suitable internal olefins include, but are not limited to, 2-butene (cis, trans, or mixtures thereof); 2-pentene (cis, trans, or mixtures thereof); 2-methyl-2-butene; 2-hexene (cis, trans, or mixtures thereof); 2-methyl-2-pentene; trans-4-methyl-2-pentene; 3-hexene (cis, trans, or mixtures thereof); 2,3-dimethyl-2-butene; 3-methyl-2-pentene (cis, trans, or mixtures thereof); A-1) may be selected from the group consisting of 2-octene, 4-octene, 2-methyl-2-butene, and 2,3-dimethyl-2-butene.

[0015] Alternatively, the internal olefins A-1) may be substituted with oxygen atoms. For example, the internal olefin compound may be of the formula alkenyl ether, wherein R 2 、R 4 、R 8 and R 10 As described above, the ether is exemplified by, for example, ethyl-1-propenyl ether (cis, trans, or mixtures thereof), which is also available from Millipore Sigma.

[0016] The starting material A) in the process described herein may optionally include, in addition to A-1) an internal olefin compound, A-2) a terminal olefin compound. The terminal olefin compound may be, for example, a terminal olefin having 2 to 16 carbon atoms per molecule. For example, octene may be provided as a mixture comprising 1-octene and one or more of the following: 2-octene (cis, trans, or a mixture thereof); 3-octene (cis, trans, or a mixture thereof); 1 and 4-octene (cis, trans, or a mixture thereof). Alternatively, the starting material A) may include a mixture of terminal octenes and internal octenes from a process for producing linear low-density polyethylene (LLDPE). The starting material A-1) may be 100% by weight of the starting material A), i.e., the A-2) terminal olefin compound is optional and its amount may be 0. Alternatively, the starting material A) may include 99% to 100% by weight of the A-1) internal olefin compound, alternatively 99% to <100% by weight of the A-1) internal olefin compound. Alternatively, the starting material A) may contain >1 wt% of terminal olefin compounds, for example when by-products from processes such as LLDPE production processes are used herein. For example, in by-products from LLDPE production, the weight ratio of A-1) internal olefin compounds to A-2) terminal olefin compounds may range from 1.2 / 1 to 1 / 1.2; alternatively from 1.1 / 1 to 1 / 1.1; alternatively 1 / 1.

[0017] The amount of the starting material A) olefin component depends on various factors, including the selection and amount of starting material A) and starting material B), the alkenyl content of starting material A), and the silicon-bonded hydrogen content of starting material B). However, the amount of the starting material A) olefin component and the amount of the starting material B) silyl hydride compound can be selected so that the molar ratio of silicon-bonded hydrogen atoms from the B) silyl hydride compound to double bonds in the A) olefin component (B / A molar ratio) can be from 100 / 1 to 1 / 100, alternatively from 5 / 1 to 1 / 5, alternatively from 1 / 1 to 1 / 5, alternatively from 3 / 1 to 1 / 3, and alternatively from 1 / 1.

[0018] B) Silyl hydride compounds

[0019] The starting material B) in the method described herein is a silyl hydride compound. The silyl hydride compound can be B-1) a silane or B-2) a polyorganohydrogensiloxane. The starting material B-1) a silane has the formula H x SiR 1 y X z , where each R 1independently selected from the group consisting of an aliphatic saturated monovalent hydrocarbon group and an aliphatic saturated monovalent halogenated hydrocarbon group, each X is an independently selected hydrolyzable substituent (e.g., a halogen or an alkoxy group), subscript x is an integer having a value from 1 to 3, subscript y is an integer having a value from 0 to 3, and subscript z = 4-xy.

[0020] In the above formula, each R 1 is an aliphatic saturated monovalent hydrocarbon group or an aliphatic saturated monovalent halogenated hydrocarbon group. Suitable monovalent hydrocarbon groups include, but are not limited to, alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyl, undecyl, and octadecyl; cycloalkyl groups such as cyclopentyl and cyclohexyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; and aralkyl groups such as benzyl, 1-phenylethyl, and 2-phenylethyl. Examples of suitable monovalent halogenated hydrocarbon groups include, but are not limited to, chlorinated alkyl groups such as chloromethyl and chloropropyl groups; fluorinated alkyl groups such as fluoromethyl, 2-fluoropropyl, 3,3,3-trifluoropropyl, 4,4,4-trifluorobutyl, 4,4,4,3,3-pentafluorobutyl, 5,5,5,4,4,3,3-heptafluoropentyl, 6,6,6,5,5,4,4,3,3-nonafluorohexyl, and 8,8,8,7,7-pentafluorooctyl; chlorinated cycloalkyl groups such as 2,2-dichlorocyclopropyl and 2,3-dichlorocyclopentyl; and fluorinated cycloalkyl groups such as 2,2-difluorocyclopropyl, 2,3-difluorocyclobutyl, 3,4-difluorocyclohexyl, and 3,4-difluoro-5-methylcycloheptyl. Each X may be a halogen atom exemplified by chlorine, fluorine, bromine, and iodine; alternatively, chlorine. Alternatively, X may be of the formula OR 1 , where R 1 As described above. Alternatively, X can be an alkoxy group, such as a methoxy group or an ethoxy group. Examples of suitable silanes for starting material B) are illustrated by trichlorosilane of the formula HSiCl3, dimethylchlorosilane of the formula Me2HSiCl, trimethoxysilane of the formula HSi(OMe)3, triethoxysilane of the formula (HSiOEt)3 or methyldimethoxysilane of the formula MeHSi(OMe)2, trimethylsilane of the formula HSiMe3 or triethylsilane of the formula HSiEt3.

[0021] Alternatively, the silyl hydride compound may comprise B-2) an organohydrogensiloxane comprising two or more siloxane units selected from: HR 1 2SiO 1 / 2 、R 1 3SiO 1 / 2 , HR 1 SiO 2 / 2 、R 1 2SiO 2 / 2 、R 1SiO 3 / 2 、HSiO 3 / 2 and SiO 4 / 2 units, provided that at least one unit per molecule contains a silicon-bonded hydrogen atom. 1 Independently selected from monovalent hydrocarbon groups and monovalent halogenated hydrocarbon groups, the monovalent hydrocarbon groups and monovalent halogenated hydrocarbon groups are free of aliphatic unsaturation and are as described above for starting material B-1). The organohydrogensiloxane can be linear, branched, cyclic, resinous, or a combination thereof. Alternatively, the organohydrogensiloxane can be linear or branched. Alternatively, the organohydrogensiloxane can be linear.

[0022] The starting material B-2) organohydrogensiloxane may have the unit formula (I): (R 3 3SiO 1 / 2 ) e (R 3 2HSiO 1 / 2 ) f (R 3 2SiO 2 / 2 ) g (R 3 HSiO 2 / 2 ) h (R 3 SiO 3 / 2 ) i (HSiO 3 / 2 ) j (SiO 4 / 2 ) k , where each R 3 Independently selected from the group consisting of: aliphatic saturated monovalent hydrocarbon group, aliphatic saturated monovalent halogenated hydrocarbon group and hydrolyzable group (wherein the monovalent hydrocarbon group and the monovalent halogenated hydrocarbon group are as described above for R 1 and the hydrolyzable substituents are as described above for X); the subscripts e, f, g, h, i, j, and k each represent the average number of units in the unit formula and have values ​​such that e≥0, f≥0, g≥0, h≥0, i≥0, j≥0, k≥0, the amount (f+g+j)≥1, and 2≤(e+f+g+h+i+j+k)≤10,000.

[0023] Alternatively, B-2) the organohydrogensiloxane may comprise units of formula (II): (R 1 2HSiO 1 / 2 ) h (R 1 3SiO 1 / 2 ) i (R 1 2SiO 2 / 2 ) j (R 1 HSiO2 / 2 ) k , where R 1 is independently selected from the group consisting of a monovalent hydrocarbon group and a monovalent halogenated hydrocarbon group, the monovalent hydrocarbon group and the monovalent halogenated hydrocarbon group having no aliphatic unsaturation, and as described above, the subscripts h, i, j, and k represent the average number per molecule of each unit and have values such that 0 ≤ h ≤ 2, 0 ≤ i ≤ 2, (h + i) = 2, 0 ≤ j < 2000, 0 < k < 2000, 0 < (j + k) < 2000, and 2 ≤ (h + k) ≤ 2000. Alternatively, h can be 2 and i can be 0. Alternatively, h can be 0 and j can be 2. Alternatively, j can be from 0 to 5, alternatively from 1 to 4, alternatively from 2 to 4, and alternatively from 3 to 3.5. Alternatively, k can be from 1 to 10, alternatively from 2 to 9, alternatively from 3 to 8, alternatively from 4 to 7, and alternatively from 5 to 6. Alternatively, i and k can be 0, h can be 2, and j can be from 0 to 1000, alternatively from 0 to 500, alternatively from 0 to 250, and alternatively from 0 to 100.

[0024] Alternatively, the starting material (B-2) organohydrogensiloxane can comprise the formula (III), the formula (IV), or a combination of both, where

[0025] Formula I(III) is R 1 3SiO(R 1 2SiO) t (R 1 HSiO) u SiR 1 3, and

[0026] Formula (IV) is R 1 [[ID=2⑧]]2HSiO(R 1 2SiO )v (R 1 2SiO) w SiR 1 2H.

[0027] In the above formulas (III) and (IV), the average value of the subscript t is in the range of 0 to 2000, the average value of the subscript u is in the range of 2 to 2000, the average value of the subscript v is in the range of 0 to 2000, and the average value of the subscript w is in the range of 0 to 2000. Each R 1As described above. Alternatively, the subscript t may be 0 to 1,000; alternatively 0 to 500; alternatively 0 to 250 and alternatively 0 to 100. Alternatively, the subscript u may be 2 to 1,000; alternatively 2 to 500; alternatively 2 to 250 and alternatively 2 to 100. Alternatively, the subscript v may be 0 to 1,000; alternatively 0 to 500; alternatively 0 to 250 and alternatively 0 to 100. Alternatively, the subscript w may be 2 to 1,000; alternatively 2 to 500; alternatively 2 to 250 and alternatively 2 to 100.

[0028] The polyorganohydrogensiloxanes used for the starting material B-2) are exemplified by:

[0029] a) dimethylhydrogensiloxy-terminated polydimethylsiloxane,

[0030] b) dimethylhydrogensiloxy-terminated poly(dimethylsiloxane / methylhydrogensiloxane),

[0031] c) dimethylhydrogensiloxy-terminated polymethylhydrogensiloxane,

[0032] d) trimethylsiloxy-terminated poly(dimethylsiloxane / methylhydrogensiloxane),

[0033] e) trimethylsiloxy-terminated polymethylhydrogensiloxane,

[0034] f) Mainly composed of H(CH3)2SiO 1 / 2 unit and SiO 4 / 2 unit composition of the resin, and

[0035] g) combinations thereof.

[0036] Polyorganohydrogensiloxanes are also commercially available, such as those available from Gelest, Inc. of Morrisville, Pennsylvania, USA, for example, HMS-H271, HMS-071, HMS-993; MS-301 and HMS-301R, HMS-031, HMS-991, HMS-992, HMS-993, HMS-082, HMS-151, HMS-013, HMS-053, HAM-301 (octyl functional), HPM-502 (phenyl functional), and HMS-HM271. Other polyorganohydrogensiloxanes include DOWSIL TM 6-3570 polymer, DOWSIL TM SH1107 fluid, XIAMETER TM MHX-11007 fluid and XIAMETER TMOFS-5057 fluid, all of which are commercially available from Dow. Methods for preparing linear, branched, and cyclic organohydrogensiloxanes suitable for use herein, such as the hydrolysis and condensation of organohalosilanes, are well known in the art, see, for example, U.S. Patent No. 3,957,713 to Jeram et al. and U.S. Patent No. 4,329,273 to Hardman et al. Methods for preparing organohydrogenpolysiloxane resins suitable for use herein are exemplified, for example, in U.S. Patent Nos. 5,310,843, 4,370,358, and 4,707,531. and U.S. Patent No. 2,823,218 to Speier et al. disclose organohydrogensiloxane oligomers and linear polymers such as 1,1,3,3-tetramethyldisiloxane; 1,1,1,3,3-pentamethyldisiloxane; 1,1,1,3,5,5,5-heptamethyltrisiloxane; bis-trimethylsiloxy-terminated polymethylhydrogensiloxane homopolymer; bis-trimethylsiloxy-terminated poly(dimethyl / methylhydrogen)siloxane copolymer; and cyclic polymethylhydrogensiloxane.

[0037] The amount of starting material B) depends on various factors, including the choice and amount of starting material A) and starting material B), the alkenyl content of starting material A), and the silicon-bonded hydrogen content of starting material B).

[0038] C) Catalyst composition

[0039] Starting material C) is a catalyst composition comprising C-1) a platinum hydrosilylation reaction catalyst and C-2) an iridium (I) complex. The iridium (I) complex may have at least one, alternatively at least two, connected or separated olefin moieties. For example, the iridium (I) complex may have at least one ligand per molecule, such as 1,5-cyclooctadiene or 2,5-norbornadiene. Alternatively, the iridium (I) complex may have two ligands per molecule, such as cyclooctene or ethylene. Alternatively, the iridium (I) complex may have at least one ligand selected from the group consisting of 1,5-cyclooctadiene, cyclooctene, 2,5-norbornadiene and ethylene. Alternatively, C) the catalyst composition may consist essentially of C-1) a platinum hydrosilylation reaction catalyst and C-2) an iridium (I) complex. Alternatively, C) the catalyst composition may consist of C-1) a platinum hydrosilylation reaction catalyst and C-2) an iridium (I) complex.

[0040] C-1) Pt hydrosilylation catalyst

[0041] Starting material C-1) is a platinum hydrosilylation catalyst. The platinum hydrosilylation catalyst promotes the reaction between alkenyl groups in the olefin compound of starting material (A) and silicon-bonded hydrogen atoms in the silyl hydride compound of starting material (B). The hydrosilylation catalyst comprises platinum. The hydrosilylation catalyst can be (C1-1) platinum metal; (C1-2) a compound of platinum metal, such as chloroplatinic acid (Spear's catalyst), chloroplatinic acid hexahydrate, platinum dichloride; (C1-3) a complex of this compound with an alkenyl-functional organopolysiloxane; or (C1-4) a platinum compound microencapsulated in a matrix or core-shell structure. Complexes of platinum with alkenyl-functional organopolysiloxanes include complexes of vinyldimethylsiloxane with platinum, such as complexes of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane with platinum (Cast's catalyst) and complexes of Pt(0) with tetramethyltetravinylcyclotetrasiloxane (Ashby's Catalyst). Alternatively, the hydrosilylation catalyst may be a compound or complex as described above (C1-5) microencapsulated in a resin matrix. The starting material C1) may be homogeneous or heterogeneous, optionally with a support. Alternatively, the starting material C1) may be homogeneous. Specific examples of platinum-containing catalysts suitable for use herein include chloroplatinic acid in hexahydrate or anhydrous form or a platinum-containing catalyst obtained by a process comprising reacting chloroplatinic acid with an aliphatically unsaturated organosilicon compound such as divinyltetramethyldisiloxane, or olefin-platinum-silyl complexes as described in U.S. Patent No. 6,605,734 to Roy. These olefin-platinum-silyl complexes can be prepared, for example, by mixing 0.015 moles (COD)PtCl2 with 0.045 moles COD and 0.0612 moles HMeSiCl2, where COD represents a cyclooctadienyl group or other platinum complexes comprising a monoanionic ligand and optionally a neutral coordinating ligand, such as a PtCOD complex having an alkenyl-functional silylalkyl group, as disclosed in U.S. Patent Nos. 11,008,353 or 11,253,846, both to Girolami et al.Other exemplary hydrosilylation catalysts are described in U.S. Patents 2,823,218 to Speier; 3,159,601 to Ashby; 3,220,972 to Lamoreaux; 3,296,291 to Chalk et al.; 3,419,593 to Willing; 3,516,946 to Modic; 3,814,730 to Karstedt; 3,928,629 to Chandra; 3,989,668 to Lee et al.; 4,766,176 to Lee et al.; 4,784,879 to Lee et al.; 5,017,654 to Togashi; 5,036,117 to Chung et al.; and 5,175,325 to Brown; as well as in EP 0 347 895 A. Suitable hydrosilylation catalysts for the starting material (C-1) are commercially available, for example, SYL-OFF. TM 4000 Catalyst and SYL-OFF TM Dow® 2700 is commercially available from The Dow Chemical Company of Midland, Michigan, USA.

[0042] Alternatively, the starting material (C-1) may be a platinum (0)-siloxane complex, which is known in the art and described, for example, in U.S. Patent No. 3,814,730, which is incorporated herein by reference. The complex may consist essentially of a chemical combination of platinum and a siloxane of the formula R m R' n R” o SiO (4-m-n-o) / 2 An unsaturated organosiloxane composition wherein each R is an independently selected monovalent hydrocarbon group without aliphatic unsaturation, each R' is an independently selected monovalent aliphatic unsaturated hydrocarbon group, each R" is selected from R' groups chemically combined with platinum, subscript m is 0 to 2, subscript n is 0 to 2, subscript o is 0.0002 to 3, and the amount (m+n+o) is 1 to 3.

[0043] The platinum (0)-siloxane complex can be prepared by combining a platinum halide and an unsaturated organosilicon material, which can be of the formula R c R' d SiO (4-c-d) / 2An organosiloxane wherein R and R' are as described above, subscript c has a value equal to 0 to 2 (inclusive), and subscript d has a value equal to 0.0002 to 3 (inclusive), and the sum of c and d is equal to 1 to 3 (inclusive). The platinum halide can be hexachloroplatinic acid or a metal salt such as NaHPtCl6·nH2O, KHPtCl6·nH2O, Na2PtCl6′nH2O, or K2PtCl6′nH2O. The complex can be prepared by contacting an unsaturated organosilicon material with a platinum halide to produce a mixture having a concentration of inorganic halogen, treating the resulting mixture to remove available inorganic halogen, and recovering the complex.

[0044] Alternatively, the unsaturated silicone material may be of the formula An unsaturated organosiloxane wherein R is an alkyl group, R' is an alkenyl group, subscript h is an integer from 1 to 3, subscript i is an integer from 1 to 3, and the amount (h+i) is ≥ 2. Suitable alkyl groups for R include methyl, ethyl, propyl, and butyl; alternatively methyl and ethyl; and alternatively methyl. Suitable alkenyl groups for R' include vinyl, allyl, and hexenyl; alternatively vinyl and allyl; and alternatively vinyl. Alternatively, the unsaturated organosiloxane may be selected from the group consisting of: 1,3-divinyl-1,1,3,3-tetramethyldisiloxane; 1,1,3-trivinyltrimethyldisiloxane; 1,1,3,3-tetravinyl-1,3-dimethyldisiloxane; and hexavinyldisiloxane.

[0045] Alternatively, the complex can be a platinum (0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex, for example, comprising the formula:

[0046]

[0047] The starting material (C-1) can be a platinum hydrosilylation catalyst or a combination of two or more of the above-mentioned platinum hydrosilylation catalysts. Alternatively, the starting material C-1) can be a platinum hydrosilylation catalyst, such as a Custer catalyst. The amount of the C-1) platinum hydrosilylation catalyst used in the method will depend on various factors, including the selection of starting material A), starting material B), and starting material C-2), however, based on the combined amount of starting material A), starting material B), and starting material C) used in step (1) of the method described herein, the amount of the C-1) platinum hydrosilylation catalyst is sufficient to catalyze the hydrosilylation reaction of SiH and terminal alkenyl groups, alternatively the amount of the catalyst is sufficient to provide at least 0.5 ppm, alternatively at least 2 ppm, alternatively at least 10 ppm, alternatively at least 15 ppm, alternatively at least 20 ppm, alternatively at least 25 ppm, and alternatively at least 30 ppm of platinum metal by mass. At the same time, the amount of catalyst is sufficient to provide up to 500 ppm, alternatively up to 250 ppm, alternatively up to 200 ppm, alternatively up to 150 ppm, and alternatively up to 100 ppm of platinum metal by mass, based on the same basis. Alternatively, the amount of starting material C-1) may be 0.5 ppm to 200 ppm, alternatively 2 ppm to 150 ppm, and alternatively 10 ppm to 100 ppm, based on the same basis.

[0048] C-2) Iridium(I)-ligand complex

[0049] Iridium(I)-ligand complexes are used in the catalyst compositions and methods described herein. The iridium(I)-ligand complexes contain at least one neutral olefin ligand per molecule. For example, the iridium(I)-ligand complexes can contain at least one ligand selected from the group consisting of 1,5-cyclooctadiene ligands, cyclooctene ligands, 2,5-norbornadiene ligands, and ethylene ligands. The iridium(I)-ligand complexes can have the formula: [Ir(R 5 ) b (R 6 ) c ] d , where subscript b is 1 or 2; R 5 is a 1,5-cyclooctadiene ligand, a cyclooctene ligand, a 2,5-norbornadiene ligand or an ethylene ligand; subscript c is 0, 1 or 2; R 6 is a ligand that can be activated from the complex at a temperature lower than the boiling point of the organohydrogensiloxane oligomer; and subscript d is 1 or 2. 6 Activation of R can be carried out by any convenient means, such as heating at a temperature below the boiling point of the silyl hydride compound, adding a silver salt, or by photochemical or electrochemical means. 6Examples of ligands include halogen atoms, β-ketoester ligands, halogenated β-ketoester ligands, alkoxy ligands, cyanoalkyl ligands, aryl ligands, and heteroaryl ligands. Examples of suitable halogen atoms include bromine (Br), chlorine (Cl), and iodine (I). Alternatively, the halogen atom can be Cl. Examples of β-ketoester ligands include acetylacetonate (acac). Examples of halogenated β-ketoesters include hexafluoroacetylacetone (hfacac). Examples of alkoxy ligands include methoxy, ethoxy, and propoxy. Alternatively, the alkoxy ligand can be methoxy. Examples of suitable cyanoalkyl ligands include CH3CN, acetonitrile, and tetrahydrofuran (THF). Examples of suitable aryl ligands include phenyl, benzyl, or indenyl. Examples of suitable heteroaryl ligands include pyridine.

[0050] In the above formula, R 5 is a 1,5-cyclooctadiene ligand, a cyclooctene ligand, a 2,5-norbornadiene ligand or an ethylene ligand. 5 may be selected from the group consisting of 1,5-cyclooctadiene ligands, cyclooctene ligands and 2,5-norbornadiene ligands. 5 may be selected from the group consisting of 1,5-cyclooctadiene ligands and cyclooctene ligands. 5 The iridium(I) complex may be a homogeneous or heterogeneous ligand, optionally with a support. Alternatively, the starting material C1) and the starting material C2) may be on the same support. Alternatively, the starting material C2) may be homogeneous.

[0051] Examples of suitable iridium(I) complexes include those shown in Table 1 below. For example, complexes containing 1,5-cyclooctadiene ligands are exemplified by, but not limited to, [Ir(I)CODCl]2, Ir(I)CODacac, Ir(I)COD2BARF, [Ir(I)COD(OMe)]2, Ir(I)COD(hfacac), IrCOD(CH3CN)2BF4, Ir(I)COD(pyridine)PF6, Ir(I)COD(indenyl), and mixtures thereof; wherein COD represents a 1,5-cyclooctadienyl group, BARF represents tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, acac represents acetylacetone, and hfacac represents hexafluoroacetylacetone. Examples of suitable iridium (I) complexes containing cyclooctene ligands are exemplified by, but not limited to, [Ir(COE)2Cl]2, where COE represents a cyclooctene group.

[0052] The amount of C-2) iridium(I) complex is sufficient to isomerize the internal alkenyl group to a terminal alkenyl group, alternatively the amount of C-2) iridium(I) complex catalyst is sufficient to provide at least 25 ppm, alternatively at least 50 ppm, alternatively at least 55 ppm, alternatively at least 60 ppm, alternatively at least 65 ppm, and alternatively at least 70 ppm by mass of iridium metal based on the combined amounts of starting material (A), starting material (B), and starting material (C) used in step (1) of the process described herein. At the same time, the amount of C-2) iridium(I) complex is sufficient to provide at most 500 ppm, alternatively at most 250 ppm, alternatively at most 200 ppm, alternatively at most 150 ppm, and alternatively at most 100 ppm by mass of iridium metal based on the same basis.

[0053] D) solvent

[0054] Starting material D) is an optional solvent that can be used to deliver one or more starting materials. A solvent can be added to promote the introduction of certain starting materials, such as B) a silyl hydride compound, such as when using a resin, and / or C) a catalyst composition. Solvents that can be used herein are those that help to fluidize the starting materials of the composition but do not react with the starting materials substantially. The solvent can be selected based on the solubility of the starting material and the volatility of the solvent. Solubility refers to that the solvent is sufficient to dissolve and / or disperse the starting material. Volatility refers to the vapor pressure of the solvent.

[0055] Suitable solvents include polyorganosiloxanes having a suitable vapor pressure, such as hexamethyldisiloxane, octamethyltrisiloxane, hexamethylcyclotrisiloxane, and other low molecular weight polyorganosiloxanes, such as DOWSIL ® 0.5 cSt to 1.5 cSt available from The Dow Chemical Company. TM 200 fluid and DOWSIL TM OS fluid.

[0056] Alternatively, the solvent may include an organic solvent. The organic solvent may be an alcohol such as methanol, ethanol, isopropanol, butanol, or n-propanol; an aromatic hydrocarbon such as benzene, toluene, ethylbenzene, or xylene; an aliphatic hydrocarbon such as heptane, hexane, or octane; a halogenated hydrocarbon such as dichloromethane, 1,1,1-trichloroethane, or methylene chloride; or a combination thereof.

[0057] The amount of D) solvent will depend on various factors, including the type of solvent selected and the amount and type of other starting materials selected for the composition. However, based on the combined weight of starting materials A), B), and c), the amount of solvent may range from 0.5% to 99.5%, alternatively from 1% to 99%, or alternatively from 2% to 90%. The solvent may be added before and / or during step 1), for example, to aid mixing and delivery. Optionally, all or part of the solvent may be removed after step 1).

[0058] Method steps

[0059] The above starting materials are used in a method for preparing an organosilicon compound. The method comprises:

[0060] 1) Mixing starting materials, which include

[0061] A) an olefin component, the olefin component comprising

[0062] A-1) an internal olefin compound, and

[0063] Optional A-2) terminal olefin compound;

[0064] B) a silyl hydride compound having at least one silicon-bonded hydrogen atom per molecule; and

[0065] C) a catalyst composition comprising

[0066] C-1) a platinum hydrosilylation catalyst, and

[0067] C-2) an iridium(I) complex; and

[0068] and optionally D) a solvent, wherein starting material A), starting material B), starting material C) and starting material D) and their amounts are as described above. Step 1) produces an isomerization and hydrosilylation reaction product comprising an organosilicon compound.

[0069] The step 1) of the method can be carried out in any convenient manner, such as mixing starting material A), starting material B) and starting material C), and starting material D when present. Typically, starting material A) and starting material B) react in a container or reactor to prepare the organosilicon compound. When the reaction is carried out at a temperature elevated or reduced as described below, the container or reactor can be heated or cooled in any suitable manner, for example, via a jacket, cover, exchanger, bath or coil. Starting material A), starting material B), starting material C) and optional starting material D) can be fed together or individually to a container, or can be arranged in a container in any order of addition and in any combination. For example, starting material A) and starting material C) and optional starting material D) can be added to a container, and starting material B) can be added thereto in an aliquot, alternatively starting material B) can be metered into a container continuously or intermittently in two or more aliquots.

[0070] Alternatively, starting material A), starting material B) and optional starting material D) can be first combined before adding, or can be added to a container sequentially, and thereafter starting material C) can be added to a container containing starting material A) and starting material B) and optional starting material D). Generally speaking, reference to "reaction mixture" herein generally refers to a mixture comprising starting material A), starting material B) and starting material C) and optional starting material D) (e.g., obtained by combining such starting materials, as described above). Each component of the catalyst composition can be added sequentially simultaneously or in any order. Starting material C-1) and starting material C-2) can be optionally combined by mixing with D) solvent before they are added to the container. Alternatively, one of starting material C-1) and starting material C-2) can be combined with D) solvent.

[0071] The method in step 1) may further comprise stirring the reaction mixture. When starting material A), starting material B), starting material C), and optional starting material D) are combined, for example, in their reaction mixture, stirring can enhance the mixing of starting material A), starting material B), starting material C), and optional starting material D) and their contact together. Such contact can independently employ other conditions, with stirring (e.g., simultaneously or sequentially) or without stirring (i.e., independently of stirring, alternatively in lieu of stirring). Other conditions can be adjusted to enhance the contact of starting material A) and starting material B), thereby enhancing the reaction (i.e., isomerization and hydrosilylation) to form a reaction product comprising an organosilicon compound.

[0072] The process in step 1) may further comprise heating the reaction mixture. The temperature depends on various factors, including the vapor pressure of starting material A) and starting material B) and starting material D) (if present), but may be 50°C to 150°C, alternatively 60°C to 100°C. Step 1) may be carried out under ambient atmosphere and pressure, alternatively under a reduced oxygen atmosphere, for example, 1% to 2% oxygen, with the balance being an inert gas, such as nitrogen.

[0073] The methods described herein may optionally further comprise one or more additional steps. For example, the method may further comprise step 2): purifying the isomerization and hydrosilylation reaction product prepared in step 1), for example to remove and / or recover unreacted starting material. Purification may be carried out by any convenient means, such as stripping and / or distillation under heating and optionally reduced pressure and / or azeotroping with a solvent, filtration, and combinations thereof. Distillation conditions typically include: (i) elevated temperature; (ii) reduced pressure; or (iii) both elevated temperature and reduced pressure. Increased or decreased means compared to room temperature and atmospheric pressure. As understood in the art, the number of trays utilized in any distillation may be optimized and may affect the rate and / or recovery of the organosilicon compound relative to the distillate produced. Distillation may be continuous or batchwise and may comprise the use of a solvent (e.g., hexane, or toluene, or other solvents described above as starting material D)) such that the distillation may be an azeotropic distillation.

[0074] As used herein, purification of the isomerization and hydrosilylation reaction product is generally defined as increasing the relative concentration of the organosilicon compound compared to other compounds with which it is combined (e.g., in the reaction product or its purified form). As understood in the art, purification can include removing other compounds from this combination (i.e., reducing the amount of impurities and / or unreacted starting materials in the isomerization and hydrosilylation reaction product that are combined with the organosilicon compound) and / or removing the organosilicon compound itself from the combination. Any suitable purification technique and / or scheme can be used. Examples of suitable purification techniques include distillation, stripping, evaporation, extraction, filtration, washing, partitioning, phase separation, adsorption, and chromatography. As will be understood by those skilled in the art, any of these techniques can be used in combination (e.g., sequentially) with any other technique to purify the isomerization and hydrosilylation reaction product. Regardless of the specific technique selected, purification of the isomerization and hydrosilylation reaction product can be performed sequentially (i.e., online) with the isomerization and hydrosilylation reaction itself and can therefore be automated. Alternatively, purification can be a separate procedure to which the isomerization and hydrosilylation reaction products comprising the organosilicon compound are subjected.

[0075] As a result of purifying the isomerization and hydrosilylation reaction products, the organosilicon compound and the unreacted olefin component can be recovered. The method may optionally further comprise step 3): repeating the method and recycling the unreacted olefin component in step 1).

[0076] Product of the method

[0077] The product prepared by the methods described herein comprises an organosilicon compound comprising a group derived from starting material A) bonded to a silicon atom from starting material B). For example, the organosilicon compound can be an organofunctional silane having the formula: R 7 x SiR 1 y X z , where the subscripts x, y, and z and R 1 and X as above, and R 7 Contains organic groups. Not wishing to be bound by theory, it is believed that R 7 It is formed by isomerizing A-1) an internal olefin compound to form a terminal olefin compound and hydrosilylating it. For example, when a linear olefin is used as A) olefin component in the above process, then R 7 For example, when the starting material A-1) is one or more of the above-mentioned internal octenes, then R 7 The product may be, for example, n-octyldimethylchlorosilane, n-octyltrichlorosilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, n-octylmethyldimethoxysilane, n-octyltrimethylsilane or n-octyltriethylsilane. Alternatively, when a branched internal olefin is used as the starting material A-1), R 7 will be branched. For example, R 7 It may be 2-methyl-2-butyl, 2,3-dimethyl-2-butyl, or other branched alkyl groups derived from the exemplary internal olefins listed above.

[0078] Alternatively, the organosilicon compound prepared by the above method may have any of the formulas described above for B-2) organohydrogensiloxanes, wherein at least one silicon-bonded hydrogen atom is replaced by R 7 For example, when B-2) comprises 1,1,3,3-tetramethyldisiloxane, the organosilicon compound may comprise the formula: Me2R 7 SiOSiMe2R 7 Alternatively, when B-2) comprises 1,1,1,3,3-pentamethyldisiloxane, the organosilicon compound may comprise the formula: Me3SiOSiMe2R 7Alternatively, when B-2) comprises 1,1,1,3,5,5,5-heptamethyltrisiloxane, the organosilicon compound may comprise a unit of formula MD R7 M, where D R7 Expression (MeR 7 SiO 2 / 2 ) of a difunctional siloxane unit, wherein R 7 As defined above. Additional examples of organosilicon compounds that can be prepared by the methods herein are described below.

[0079] Example

[0080] The following examples are provided to illustrate the present invention to those skilled in the art and should not be construed as limiting the invention set forth in the claims. The starting materials used in these examples are summarized in Table 1 below.

[0081] Table 1 - Starting materials

[0082]

[0083]

[0084] In this Reference Example 1, samples were prepared as follows: In a glove box, vials were placed on a heating block. Olefin and SiH compound were added to each vial, catalyst was added, and the vial was capped before heating. The vial was then heated to 60°C while stirring. After 1 hour and 4 hours at 60°C, each sample was subjected to a 40% ionization reaction. 1 H NMR spectroscopy was used to monitor the progress of the reaction. The starting materials, amounts used, and results are shown in Table 2 below.

[0085]

[0086]

[0087] With reference to the data in Table 2 above, Comparative Example 1, Comparative Example 4 and Comparative Example 5, as well as Working Example 3 and Working Example 5 to Working Example 14, each used the same olefin compound (2-octene) and silyl hydride compound (MD'M). These results indicate that not all iridium complexes (Comp 4 and Comp 5) can be combined with the Custer catalyst to provide reaction rate enhancement or yield improvement (>20% yield after 4 hours) under the test conditions. Examples 5 to 14 indicate that the combined use of the Custer catalyst with an Ir(I) complex comprising a COD or COE Ir(I) fragment provides synergistic results with various counteracting ligands (such as Cl, acac, or OMe).

[0088] In addition, Comparative Example 2 shows that when using Pt catalyst instead of Ir catalyst, the yield is poor under the conditions tested after 1 hour, 4 hours and 24 hours. Comparative Example 1 shows that when using Ir catalyst instead of Pt catalyst, the yield is poor under the conditions tested after 1 hour, 4 hours and 24 hours. Comparative Example 3 shows that when using insufficient Ir catalyst in combination with Pt catalyst, the yield is still poor. Working Example 1 to Working Example 6 show that using the same olefin component (2-octene) as in Comparative Example 1 to Comparative Example 3, silyl hydride compound (MD'M) and catalyst (Kars catalyst) and [Ir (COD) Cl] 2, but using the amount of each catalyst as described herein, results in a significantly improved yield than Comparative Example 1 to Comparative Example 3. These examples show that the combination of C-1) platinum hydrosilylation reaction catalyst and C-2) iridium (I) complex of the amount described herein produces a synergistic effect of the yield that unexpectedly improves.

[0089] In Examples 15 to 19, various internal olefin compounds and silyl hydride compounds were also tested using the catalyst system of the present invention. Comparative Examples 6 and 7 used the same silyl hydride compounds and olefin components as Example 15, but these results show that the combination of the platinum hydrosilylation catalyst (Cast's catalyst) and the Ir complex ([Ir(COD)Cl]2) in the amounts described herein produced improved yields and increased reaction rates in Example 15. Compared to Comparative Example 7, which contained 10 ppm of each catalyst, Example 15 had a 52% yield after just one hour, which only achieved a 16% yield after one hour and showed no increase in yield after four hours. Comparative Example 8 used the same silyl hydride compound and olefin components as Example 16, but when 10 ppm of Castor's catalyst and 100 ppm of [Ir(COD)Cl]2 were included, Example 16 showed improved yields. Comparative Example 9 and Example 17 each used MD'M and 23DM2B, and Example 17 had an improved conversion rate when 100 ppm of [Ir(COD)Cl]2 was included. Comparative Example 10 and Example 19 each used MD'M and 23DM2B, and Example 19 had an improved conversion rate when 100 ppm of [Ir(COD)Cl]2 was included. These examples demonstrate that the combination of starting material C-1) and starting material C-2) in the amounts described herein is effective for isomerization and hydrosilylation reactions of different olefin compounds and silyl hydride compounds. Furthermore, the reactions in the working examples proceeded faster than in the comparative examples using the same A) olefin compound and B) silyl hydride compound.

[0090] Industrial Applicability

[0091] The Examples and Comparative Examples presented above demonstrate that the combination of a platinum hydrosilylation catalyst and an iridium (I) complex, used in the amounts described herein, yields the unexpected benefits of increased feedstock efficiency, increased yields, and / or increased reaction rates for the hydrosilylation of various internal olefins and silyl hydride compounds. Without wishing to be bound by theory, the present process has improved recyclability and recyclability by reducing the amount of waste generated compared to processes involving only the hydrosilylation of terminal olefin compounds.

[0092] Definition and Usage of Terms

[0093] Unless otherwise indicated, all amounts, ratios and percentages herein are by weight. Unless otherwise indicated in the context of this specification, the articles "a", "a kind of" and "said" each refer to one (a kind) or more (a variety). Unless otherwise indicated, the singular includes plural meanings. Summary of the invention and specification abstract are hereby incorporated by reference. The transition phrases "comprising", "consisting essentially of ... " and "consisting of ... " are used as described in the revised version 08.2017, §2111.03I., II. and III of the Patent Examination Procedure Manual, Ninth Edition, last revised in January 2018. Any feature or aspect of the present invention may be used in combination with any other feature or aspect described herein. The abbreviations used herein have the definitions in Table 3.

[0094] Table 3 - Abbreviations

[0095] abbreviation definition acac Acetylacetone ℃ degrees Celsius DOW The Dow Chemical Company in Midland, Michigan, USA g gram h Hour hfacac Hexafluoroacetylacetone Me methyl NMR Nuclear magnetic resonance imaging Ph Phenyl ppm One millionth by weight THF Tetrahydrofuran

Claims

1. A method for preparing an organosilicon compound, wherein the method comprises: 1) Mixing starting materials, the starting materials comprising A) an olefin component, the olefin component comprising A-1) an internal olefin compound, wherein the internal olefin compound is linear or branched, has at least 4 carbon atoms per molecule, and has at least one internal double bond per molecule; and Optional A-2) a terminal olefin compound, wherein the terminal olefin compound is linear or branched, has at least 4 carbon atoms per molecule, and has at least one terminal double bond per molecule; B) a silyl hydride compound having at least one silicon-bonded hydrogen atom per molecule; C) a catalyst composition comprising At least 0.5 ppm of C-1) a platinum hydrosilylation catalyst; and at least 25 ppm of C-2) an iridium(I) complex having at least one ligand, said iridium(I) complex comprising one or more attached or separated olefinic moieties; Thereby, an isomerization and hydrosilylation reaction product comprising the organosilicon compound is produced.

2. The process according to claim 1, wherein the internal olefin compound A-1) comprises an internal olefin of formula A-1-1): where R 2 With empirical formula -C p H (2p+1) , where the subscript p≥1; and R 4 With empirical formula -C q H (2q+1) , where subscript q≥1; R 8 With empirical formula -C r H (2r+1) , where subscript r≥0; and R 10 With empirical formula -C s H (2s+1) , wherein the subscript s≥0; and the amount (p+q+r+s) is 2 to 14.

3. The method of claim 2, wherein the internal olefin is selected from the group consisting of 2-octene, 4-octene, 2-methyl-2-butene, and 2,3-dimethyl-2-butene.

4. The method according to claim 3, wherein A-2) the terminal olefin compound is present and comprises 1-octene.

5. The process according to claim 1, wherein A-1) the internal olefin component comprises the formula alkenyl ether, wherein R 2 With empirical formula -C p H (2p+1) , where the subscript p≥1; and R 4 With empirical formula -C q H (2q+1) , where subscript q≥1; R 8 With empirical formula -C r H (2r+1) , where subscript r≥0; and R 10 With empirical formula -C s H (2s+1) , wherein the subscript s≥0; and the amount (p+q+r+s) is 2 to 14.

6. The method of claim 6, wherein the alkenyl ether comprises ethyl-1-propenyl ether.

7. The method of claim 1, wherein the silyl hydride compound is selected from the group consisting of: B-1) silanes having at least one silicon-bonded hydrogen atom per molecule, B-2) organohydrogensiloxanes.

8. The method according to claim 7, wherein B-1) the silane has the formula H x SiR 1 y X z , where each R 1 independently selected from the group consisting of an aliphatic saturated monovalent hydrocarbon group and an aliphatic saturated monovalent halogenated hydrocarbon group, each X is an independently selected hydrolyzable substituent, subscript x is an integer having a value from 1 to 3, subscript y is an integer having a value from 0 to 3, and subscript z=4-xy.

9. The method according to claim 7, wherein B-2) the polyorganohydrogensiloxane comprises units of the formula: (R 1 2HSiO 1 / 2 ) h (R 1 3SiO 1 / 2 ) i (R 1 2SiO 2 / 2 ) j (R 1 HSiO 2 / 2 ) k , wherein each R 1 is independently selected from the group consisting of monovalent hydrocarbon groups and monovalent halogenated hydrocarbon groups, the monovalent hydrocarbon groups and monovalent halogenated hydrocarbon groups having no aliphatic unsaturation, the subscripts h, i, j and k represent the average number of each unit per molecule, and have values such that 0 ≤ h ≤ 2, 0 ≤ i ≤ 2, (h + i) = 2, 0 ≤ j < 2000, 0 < k < 2000, 0 < (j + k) < 2000 and 2 ≤ (h + k) ≤ 2000.

10. The process according to any one of claims 1 to 9, wherein C-1) the platinum hydrosilylation reaction catalyst is selected from the group consisting of a Custer catalyst, a Spier catalyst and platinum on a support.

11. The method according to any one of claims 1 to 10, wherein C-2) the iridium(I)-ligand complex has the formula [Ir(R 5 ) b (R 6 ) c ] d , where subscript b is 1 or 2; each R 5 independently selected from the group consisting of 1,5-cyclooctadiene ligands, cyclooctene ligands, 2,5-norbornadiene ligands and vinyl ligands; subscript c is 0, 1 or 2; R 6 is a ligand that can be activated from the complex at a temperature lower than the boiling point of the silyl hydride compound; and subscript d is 1 or 2.

12. The method of claim 11, wherein the iridium(I)-ligand complex in C-2) is selected from the group consisting of: chloro-1,5-cyclooctadiene iridium(I) dimer; 1,5-cyclooctadiene(acetylacetonate)iridium(I); bis(1,5-cyclooctadiene)iridium(I) tetrakis[3,5-bis(trifluoromethyl)phenyl]boronic acid; di-μ-methoxybis(1,5-cyclooctadiene)diiridium(I); chlorobis(cyclooctene)iridium(I) dimer; 1,5-cyclooctadiene(hexafluoroacetylacetonate)iridium(I); bis(acetonitrile)(1,5-cyclooctadiene)iridium(I) tetrafluoroborate; bis(pyridine)(1,5-cyclooctadiene)iridium(I) hexafluorophosphate; 1,5-cyclooctadiene(≈5-indenyl)iridium(I); and mixtures thereof.

13. The method according to claim 1, further comprising: 2) purifying the isomerization and hydrosilylation reaction product comprising the organosilicon compound, thereby recovering the organosilicon compound and unreacted olefin component; as well as Optionally 3) repeating the process and recycling the unreacted olefin component in step 1).

14. A catalyst composition suitable for isomerization and hydrosilylation reactions, wherein the catalyst composition consists of: At least 0.5 ppm of C-1) a platinum hydrosilylation catalyst; and At least 25 ppm of C-2) an iridium(I) complex having at least one ligand, said iridium(I) complex comprising one or more attached or separated olefinic moieties.

15. The catalyst composition according to claim 14, wherein C-1) the platinum hydrosilylation reaction catalyst is present in an amount of 0.5 ppm to 500 ppm; and C-2) The iridium (I) complex has at least one ligand selected from the group consisting of 1,5-cyclooctadiene, cyclooctene, 2,5-norbornadiene, and ethylene; and the iridium (I) complex is present in an amount of 25 ppm to 500 ppm.

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