Alkoxylations using polyhedral borate catalysts

Abstract

Alkoxylations are performed by combining an alkylene oxide with a starter and a polyhedral borate catalyst. The polyhedral borate catalyst has the form [Cat+]n[B12XuYv]n- and / or [Cat+]m[B10XwYz]m-. The polyhedral borate catalysts are extremely active and therefore produce very high alkoxylation rates. When used to polymerize propylene oxide, the catalysts produce alkoxylated products that have high proportions of primary hydroxyl groups.

Description

ALKOXYLATIONS USING POLYHEDRAL BORATE CATALYSTS CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and all advantages of U. S. provisional patent application no. 63 / 714,206 filed on 31 October 2024, the disclosure of which is incorporated herein by reference in its entirety.FIELD OF THE INVENTION

[0002] This disclosure relates to a process for alkoxylating a starter compound with one or more alkylene oxides.DESCRIPTION OF THE RELATED ART

[0003] Alkylene oxide polymers and copolymers are produced globally in large quantities. Polyether polyols, for example, are an important raw material for producing polyurethanes. Among other things, they are used to make high resiliency, molded, or rigid foams. Polyether monols are used, for example, as surfactants and industrial solvents, among other uses. Carbonate- and ester-modified alkylene oxide polymers also find uses in these and other applications.

[0004] Polyether monols and polyols are produced by alkoxylating a starter compound by reaction with an alkylene oxide. The starter compound has one or more functional groups at which the alkylene oxide can react to produce a polyether. The main functions of the starter compound are to provide molecular weight control and to establish the number of hydroxyl groups the polyether will have.

[0005] A catalyst is needed to obtain economical reaction rates. The most commonly used catalysts are alkali metal hydroxides such as potassium hydroxide and the so-called double metal cyanide (DMC) catalyst complexes, of which zinc hexacyanocobaltate catalyst complexes are the most commercially important type.

[0006] Alkali metal hydroxides provide the benefits of low catalyst costs and acceptable reaction rates. They are versatile in that they effectively catalyze alkoxylations using many alkylene oxides. The product polyether usually, but not always, has a narrow molecular weight distribution. Nonetheless alkali metal hydroxides have well-known drawbacks. Alkali metal hydroxide catalysts promote a side reaction that forms unsaturated monoalcohols, which become alkoxylated to form unwanted monofunctional species. The presence of these unwanted monofunctional species can also broaden molecular weight distribution. Another drawback is that alkoxylated products made using these catalysts need to be neutralized and purified to remove catalyst residues, which adds significant capital and operating expense to the manufacturing process.

[0007] DMC catalysts provide rapid reaction rates compared to alkali metal catalysts, even when used at very low catalyst concentrations. In addition, they have distinct and important advantages over alkali metal catalysts. The DMC catalysts rarely, if at all, promote the side reaction that produces monofunctional by-products, so the hydroxyl functionality of the product is close to the theoretical value (as defined by the starter). A second main advantage is that no neutralization step is needed. The catalyst residues often can be left in the product, unlike the case when alkali metal hydroxides are used as the polymerization catalyst. This can result in significantly lower production costs. Nonetheless, DMC catalysts have disadvantages as well. They perform poorly in the presence of high concentrations of hydroxyl groups, and especially in the presence of low molecular weight starter compounds like glycerin that have hydroxyl groups in the 1,2- or 1,3- positions with respect to each other. Therefore, DMC catalysts have not been found to be useful to produce low molecular weight polyethers.

[0008] Various Lewis acids and Bronsted acids have been evaluated as polymerization catalysts. EP2691440B1 describes short-chain polyether polyols using a low molecular weight starter, using an acid catalyst and a DMC catalyst in sequence. Among the acids are Lewis acids such as boron trifluoride, antimony pentafluoride, phosphorus pentafluoride and Bronsted acids such as triflic acid, fluorosulfonic acid, fluoroantimonic acid, perchloric acid, tetrafluoroboric acid, hexafluorophosphoric acid and carborane (HCHB^CI-|i). Reaction in the presence of the acid catalyst produces a 50 to 200 equivalent weight intermediate that is further alkoxylated using a double metal cyanide catalyst to form the final product. US Pat.8,680,211 describes using “superacids” to produce hybrid polyester-polyether polyols; carborane (HCHB^ ^Cl<| <|) appears in a list of superacid candidates.

[0009] WO 2024 / 086488, WO 2024 / 086489, and WO 2024 / 086490 describe various phosphonium catalysts useful for alkoxylation reactions. The positively charged phosphonium cation is associated with a weakly coordinating anion, of which®12®r12^- arementioned.BRIEF SUMMARY

[0010] This disclosure is in one aspect a method for producing an alkoxylate, the method comprising combining (1) a polyhedral borate, (2) at least one starter, and (3) at least one alkylene oxide, and subjecting the resulting combination to alkoxylation conditions such that the starter and alkylene oxide react to produce an alkoxylate, wherein the polyhedral borate comprises [Cat+]nBi2 |Yv]n‘ and / or [Cat+]m[B^QXwYz]m‘, wherein Cat+is a proton or a protonated neutral molecule, each X is independently selected from hydrogen, halogen; C-j.40 hydrocarbyl, which is optionally substituted with halogen; -OH, -OR -SH, -SR cyanide,nitrite or triflate, each Y is independently selected fromPH2(R1),cyclic thioether, cyclic dithioether, ©(R^, cyclic ether, cyclic diether, 0=S(R^)2, S(O)2(R^)2> and 0=P(R1)3, where each R^ is independently C1-35 hydrocarbyl, which is optionally substituted with halogen, v is 0 or 1, n is (2-v), u is (12-v), z is 0 or 1, m is (2-z), and w is (10-z).DETAILED DESCRIPTION

[0011] This disclosure is in one aspect a method for producing an alkoxylate. The method comprises: combining (1) a polyhedral borate, (2) at least one starter, and (3) at least one alkylene oxide; and subjecting the resulting combination to alkoxylation conditions such that the starter and alkylene oxide react to produce an alkoxylate. The polyhedral borate comprises [Cat+]nBi2 |Yv]n‘ and / or [Cat+]m[B^QXwYz]m‘. Cat+is a proton or a protonated neutral molecule. Each X is independently selected from hydrogen, halogen; C-^Q hydrocarbyl, which is optionally substituted with halogen; -OH, -OR -SH, -SR cyanide, nitrite or triflate. Each Y is independently selected from NH3, NH2(R1), NH(R1)2, NR13, PH3, PH2(R1),S(R1)2> cyclic thioether, cyclic dithioether, O(R^)2> cyclic ether, cyclic diether, O=S(R^)2, S(O)2(R^)2> and O=P(R1)3, where each R”* is independently C-i.gg hydrocarbyl, which is optionally substituted with halogen. Moreover, v is 0 or 1, n is (2-v), u is (12-v), z is 0 or 1, m is (2-z), and w is (10-z). In various embodiments, R^ in each case is C-,.4 alkyl or phenyl. In general, n is 2 when v or z is zero, and 1 when v or z is one.

[0012] The method of the disclosure offers several advantages, from both process and product perspectives. These are detailed below.

[0013] Process advantages include rapid polymerization rates; the ability to alkoxylate starters that have a wide range of molecular weights, in particular low molecular weight starters that have hydroxyl equivalent weights of 30 to 75; the ability to use significantly lower levels of catalyst than needed with alkali metal hydroxides, thereby reducing costs and permitting at least in some cases the polyols to be used without the need to first remove catalyst residues. The polyhedral borate catalysts are reasonably inexpensive compared to, for example, carboranes.

[0014] The polyhedral borate comprises a salt of a [Cat+] cation and a [B^2XuYv]n‘ anion or [B^QXwYz]m‘ anion. The [B-|2xuYvln' and [B^QXwYz]m‘ anions each take the form of a polyhedral cage structure in which each boron atom is bonded to four or five other boronatoms, as shown, for example, in Inorg. Chem. 1964, 3, 2, 159-167 and J. Am. Chem. Soc.1967, 89, 13, 3361-3362. The charge on the [B12XuYv]n- or [B10XwYz]m' anion is delocalized. The polyhedral borate may be associated with one or more waters of hydration, such as 1 to 10 or 2 to 6 waters of hydration.

[0015] Each X may, but generally does not, contain organically bonded halogen (J.e., halogen bonded to a carbon atom, as in -CF3 -CCI3 or triflate). In various embodiments, each X is hydrogen, halogen (including fluorine, chlorine, bromine, iodine), or hydroxyl. In further embodiments, each X is hydrogen, chlorine, bromine or hydroxyl. The X groups may be the same or different.

[0016] Specific examples of Y include, for example, trimethyl amine, triethyl amine, triphenylamine, trimethyl phosphine, triethyl phosphine, triphenyl phosphine, dimethylsulfide, diethyl sulfide, diphenyl sulfide, diethyl ether, 1,4-dioxane, tetrahydrofuran, trimethyl phosphine oxide and triphenyl phosphine oxide.

[0017] The Cat+cation is a proton or a protonated neutral molecule, which neutral molecule is a weak Lewis base capable of being protonated by the acid Hn[B^2XuYv]n‘ andHn[B10xwYzlm'tof°rm a cat'oncarrying a charge of +1. Hydronium (H3O+) is an especially useful cation. Other protonated cations include other oxoniums such as a protonated alcohol and a protonated ether; a protonated arene; a protonated alkene; a protonated thiol; a protonated thiol ether; a protonated dialkylformamide such as protonated dimethyl formamide; a protonated dialkylsulfoxide such as protonated dimethylsulfoxide; a protonated sulfone; and a protonated nitrile such as protonated acetonitrile.

[0018] Examples of polyhedral borates include: [Cat+]2[B-[Cat+]2[B12F12]2' • ZH2O, [Cat+]2[B12CI12]2' • ZH2O, [Cat+]2[B12Br12]2' • ZH2O, ZH2O, [Cat+]2[B12I12]2- • ZH2O, [Cat+]2[B12(OH)12]2- • ZH2O, [Cat+]2[B12HaF12.a]2- • ZH2O, [Cat+]2[B12HaCI12.a]2- • ZH2O, [Cat+]2[B12HaBr12.a]2- • ZH2O, [Cat+]2[B12Hal12.a]2- • ZH2O, [Cat+]2[B12Ha(OH)12.a]2- • ZH2O, [Cat+]2[B12FaCI12.a]2- • ZH2O, [Cat+]2[B12FaBr12.a]2- • ZH2O,[Cat+]2[B12Fal12.a]2- • ZH2O, [Cat+]2[B12Fa(OH)12.a]2- • ZH2O, [Cat+]2[B12ClaBr12.a]2- • ZH2O, [Cat+]2[B12Clal12.a]2- • ZH2O, [Cat+]2[B12Cla(OH)12.a]2- • ZH2O, [Cat+]2[B12Bral12.a]2- • ZH2O,[Cat+]2[B12Bra(OH)12.a]2- • ZH2O, [Cat+]2[B12la(OH)12.a]2- • ZH2O, [Cat+]2[B10H10]2- • ZH2O, [Cat+]2[B10F10]2- • ZH2O, [Cat+]2[B10CI10]2- • ZH2O, [Cat+]2[B10Br10]2- • ZH2O, [Cat+]2[B10l10]2- • ZH2O, [Cat+]2[B10(OH)10]2- • ZH2O, [Cat+]2[B10HbF10.b]2- • ZH2O, [Cat+]2[B10HbCI10.b]2- • ZH2O, [Cat+]2[B10HbBr10.b]2- • ZH2O, [Cat+]2[B10Hbl10.b]2- • ZH2O, [Cat+]2[B10Hb(OH)10.b]2- • ZH2O, [Cat+]2[B10FbCI10.b]2- • ZH2O, [Cat+]2[B10FbBr10.b]2- • ZH2O, [Cat+]2[B10Fbl10.b]2- • ZH2O, [Cat+]2[B10Fb(OH)10.b]2- • ZH2O, [Cat+]2[B10ClbBr10.b]2- • ZH2O, [Cat+]2[B10Clbl10.b]2- • ZH2O, [Cat+]2[B10Clb(OH)10.b]2- • ZH2O, [Cat+]2[B10Brbl10.b]2- • ZH2O, [Cat+]2[B10Brb(OH)10.b]2- • ZH2O, andeach a is 1 to 11, each b is 1 to 9, and each Cat+is a proton or other cation as described above. In various embodiments: each Cat+is oxonium, or optionally hydronium; and each Z is 0 to 12, 1 to 10, or 2 to 6.

[0019] Further examples of polyhedral borates include: [Cat+][B^2H^(NR”'3)]‘ • ZH2O,[Cat+][B12Br11(SR12)]’ • ZH2O, [Cat+][B12I11(SR12)]’ • ZH2O, [Cat+][B10H9(NR13)J- • ZH2O, [Cat+][B10F9(NR13)J- • ZH2O,[Cat+][B10CI9(NR13)J- • ZH2O, [Cat+][B10Br9(NR13)J- • ZH2O,[Cat+][B10l9(NR13)J- • ZH2O, [Cat+][B10H9(PR13)J- • ZH2O,[Cat+][B10F9(PR13)J- • ZH2O, [Cat+][B10CI9(PR13)r • ZH2O,[Cat+][B10Br9(PR13)]- • ZH2O, [Cat+][B10lg(PR13)]- • ZH2O,[Cat+][B10H9(SR12)J- • ZH2O, [Cat+][B10F9(SR12)J- • ZH2O,[Cat+][B10CI9(SR12)]‘ • ZH2O, [Cat+][B10Br9(SR12)]_• ZH2O, and [Cat+][B^gl9(SR^2)]‘ • ZH2O, where each Cat+is a proton or other cation as described above. In various embodiments: each Cat+is oxonium, or optionally hydronium; each Z is 0 to 12, 1 to 10, or 2 to 6; and each R”* is as described above, or optionally methyl, ethyl, butyl, or phenyl.

[0020] The polyhedral borate may be synthesized using known methods, such as those described in Inorg. Chem. 19643 159-167, Inorg. Chem. 19643(10) 1456-1463 and US Pat.3,245,056, J. Organomet. Chem. 2021, 949, 121697 and Inorg. Chem. 2023, 62, 15084. Alkali metal [B^2XuYv]n‘ and [B^gXwYz]n‘ salts are useful starting materials; certain of these such as Na2[B.|QH.|Q], Na2[B^2H^2], CS2[B^QH^Q] and Cs2[B^2H^2] are commercially available. Hydrogens can be replaced with halogens by treatment with halogenating agents such as elemental fluorine, elemental chlorine, elemental bromine, elemental iodine, trichloroisocyanuric acid, NaOBr, HOBr, NaOCI, HOCI, N-bromosuccinimide and the like. Hydrogens can be replaced with hydroxyl groups by treatment with sulfuric acid. Alkali metal or other water-soluble metal salts can be converted to oxonium salts by contacting a solution or suspension of the salt in water (to make a hydronium salt) or an alcohol or ether with a strong acid ion exchange resin in the hydrogen form. Alternatively, an alkali metal or other water-soluble metal salt may be converted to an R3NH+salt, where R is alkyl, especially C^_ 4 alkyl, by reaction with a trialkylamine hydrochloride having the form R3NH+CI‘. The R3NH+salt also can be converted to the hydronium salt by contacting an aqueous solution or suspension of the R3NH+salt with a strong acid ion exchange resin in the hydrogen form.

[0021] One or more starter compounds is alkoxylated according to this disclosure. The starter compound has one or any larger number of functional groups capable of being alkoxylated. The functional groups may be, for example, primary, secondary, or tertiary hydroxyl, or thiol. In various embodiments, the starter contains 1 or more such functional groups, optionally 2 or more of such functional groups, and may contain as many as 12 or more of such functional groups.

[0022] In certain embodiments, the functional groups of the starter are all hydroxyl groups and the starter does not contain primary and / or secondary amino groups or thiol groups. In some embodiments, the starter compound will have 2 to 8, 2 to 6, or 2 to 4 hydroxyl groups.

[0023] The starter compound may have an equivalent weight of 9 g / equivalent (in the case of water) to 6000 g / equivalent or more. In some embodiments, the starter compound has an equivalent weight of 9 to 4000, 9 to 2500, 30 to 1750, 30 to 1400, 30 to 1000, 30 to 500, or 30 to 250, g / equivalent.

[0024] Equivalent weight of an alcohol or polyol is conveniently determined using titration methods such as ASTM 4274-16, which yield a hydroxyl number in mg KOH / gram of polyol that can be converted to equivalent weight using the relation equivalent weight = 56,100 * hydroxyl number.

[0025] Suitable starters include vinyl alcohol, propenyl alcohol, allyl alcohol, acrylic acid, hydroxyethyl acrylate, hydroxyethyl methacrylate,alkanol, phenol, cyclohexanol, an alkylphenol, water (considered for purposes of this disclosure as having two hydroxyl groups), ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,4-butane diol, 1,6-hexane diol, 1,8-octane diol, cyclohexane dimethanol, glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, sorbitol, sucrose, sucrose, mannitol, phenol, polyphenolic starters such as bisphenol A or 1,1,1-tris(hydroxyphenyl)ethane, and the like.

[0026] Other suitable starters include hydroxyl-terminated polyethers (including alkoxylates, especially ethoxylates and / or propoxylates, of hydroxyl-containing starters including those just described) having hydroxyl equivalent weights less than that of the product of the polymerization. Such a polyether starter may have, for example, a hydroxyl equivalent weight of at least 125 and up to 6000, up to 4000, up to 2500, up to 1750, up to 1500, up to 1000, up to 500, or up to 250, g / equivalent. In some embodiments, the polyether starter may be a homopolymer of propylene oxide and / or a random or block copolymer of propylene oxide and one or more other alkylene oxides (especially ethylene oxide), which has a hydroxyl equivalent weight as mentioned in this paragraph and in which no more than 25%, no more than 15%, or no more than 10% of the hydroxyl groups are primary.

[0027] The alkylene oxide(s) may be, for example, ethylene oxide, 1,2-propylene oxide (generally referred to herein as “propylene oxide”), oxetane, 1,2-butene oxide, 2-methyl-1,2-butaneoxide, 2,3-butane oxide, tetra hydrofuran, epichlorohydrin, hexene oxide, octene oxide, styrene oxide, divinyl benzene dioxide, a glycidyl ether such as Bisphenol A diglycidyl ether, epichlorohydrin or other polymerizable oxirane. In some embodiments, the alkylene oxide is 1,2-propylene oxide, ethylene oxide, or a mixture of at least 50% (or optionally at least 80%) by weight propylene oxide and correspondingly up to 50% (or optionally up to 20%) by weight ethylene oxide.

[0028] The alkoxylation is performed by combining the starter, polyhedral borate, alkylene oxide(s), and optionally comonomer, and then subjecting the resulting combination to alkoxylation conditions. The alkoxylation proceeds at a wide range of temperatures, such as from -100°C to 250°C or more. In some embodiments, the alkoxylation temperature is at least 80°C, at least 100°C, at least 120°C, or at least 130°C. In various embodiments, the polymerization temperature does not exceed 190°C, and optionally does not exceed 180°C. The alkoxylation reaction usually is performed at a super-atmospheric pressure, but can be performed at atmospheric pressure or even a sub-atmospheric pressure.

[0029] Enough of the polyhedral borate is used to provide a commercially reasonable alkoxylation rate, but it is generally desirable to use as little of the polyhedral borate as possible consistent with reasonable alkoxylation rates, as this both reduces the cost for the catalyst and can eliminate the need to remove catalyst residues from the product. The amount of polyhedral borate may be, for example, sufficient to provide 50 to 10,000 ppm of the polyhedral borate (including the weight of the cation and any waters of hydration), based on the weight of the starter. In specific embodiments, the amount of polyhedral borate may be at least 100 ppm or at least 200 ppm on the foregoing basis, and up to 5,000 ppm, up to 2,500 ppm, up to 1500 ppm, or up to 1000 ppm.

[0030] The alkoxylation reaction can be performed batch-wise, semi-continuously (including with continuous addition of starter as described in US Pat. 5,777,177) or continuously.

[0031] The crude alkoxylation product obtained may contain a small amount of unreacted alkylene oxide; small quantities of unreacted starter compound; and / or small quantities of other organic impurities and water. Volatile impurities (including unreacted alkylene oxides) should be flashed or stripped from the product. The crude product typically contains residues of the polyhedral borate catalyst. It is generally acceptable to leave these residues in the product, but these can be removed if desired. Moisture and volatiles can be removed by stripping the product.

[0032] The process of the disclosure is especially useful for alkoxylating a starter with 1 to 10, 1 to 5, 1 to 4, or 2 to 4 moles of alkylene oxide per equivalent of hydroxyl, or thiol group on the starter. Each alkoxylation reaction produces a hydroxyl group that can be the site of further alkoxylation. Thus, the process of the disclosure is especially suitable for producing polyether monols and, in particular, polyether polyols that have number average molecular weights of 125 to 1500 g / mol, 150 to 1500 g / mol, 150 to 1200 g / mol, 200 to 1000 g / mol, or 200 to 600 g / mol, and which have 1 to 8, or 2 to 8, hydroxyl groups per molecule. One exemplary product is a polyether triol having a molecular weight of 200 to 600.

[0033] The polyhedral borate catalyst generally favors the formation of primary hydroxyl groups when the alkylene oxide contains 3 or more carbon atoms, such as 1,2-propylene oxide and 1,2-butylene oxide. In particular, propylene oxide reacts in the presence of the polyhedral borate catalyst to produce a -CH(CH3)-CH2-OH group about 50 to 90% of the time. The hydroxyl group in such a case is primary. Some smaller proportion propylene oxide reacts to produce secondary hydroxyl, i.e., a -CH2-CH(CH3)-OH group. The ability to produce alkoxylated products in which the hydroxyl groups are mainly primary, without using ethylene oxide, has significant advantages in certain instances, such as in cases in which ethylene oxide is not readily available or when hydrophilicity associated with the presence of polymerized ethylene oxide is undesirable.

[0034] Alkoxylated products having 2 or more hydroxyl groups produced in accordance with the disclosure are useful for making polyurethanes. Due to their generally low molecular weights, they are particularly useful for making rigid polyurethane foams and structural, non-elastomeric polyurethanes. In addition, the alkoxylated products are useful as starters for preparing higher molecular weight polyethers.

[0035] Polyether monols produced in accordance with the disclosure are useful as surfactants or as industrial solvents, among other uses.EXAMPLES

[0036] The following examples are provided to illustrate the invention of this disclosure but are not intended to limit the scope thereof. All parts and percentages are by weight unless otherwise indicated.Catalyst Preparation Procedure

[0037] [H3O+]2[B12Cl12] • 4H2O:An aqueous solution of Cs2[B12H12]isreacted with trichloroisocyanuric acid to produce Cs2[B12Cl12]as awhite crystalline solid. The Cs2[B<|2CI-|2]isthen contacted with triethylamine hydrochloride in water (10 mL). [Et3NH]2[B12Cl12] precipitates as a white solid. The [Et3NH]2[B12Cl12] 'sthen reacted with sodium hydroxide and cesium chloride to produce Cs2[B12Cl12] that is substantially free from impurities, which is recrystallized. The Cs2[B12Cl12] is dissolved in water stirred with a strong acid cation exchange resin in the acid (H+) form to yield [H3O+]2[B12Cl12]

[0038] [H3O+]2[B12Br12] • 4H2O:Cs2[B12H12] is dissolved in water and stirred with a strong acid cation exchange resin in the acid (H+) form to yield [H3O+]2[B12H12], A solution of [H3O+]2[B12H12] is reacted with trichloroisocyanuric acid in the presence of excess sodium bromide to give [H3O+]2[B12Br12], The solution of [H3O+]2[B12Br12] is treated with sodium sulfite and then contacted with triethylamine hydrochloride in water (10 mL). [Et3NH]2[B12Br12] precipitates as a white solid. The [Et3NH]2[B12Br12] is then reacted with sodium hydroxide and cesium chloride to produce Cs2[B12Br12] that is substantially free from impurities, which is then recrystallized. The Cs2[B12Br12] is dissolved in water stirred with a strong acid cation exchange resin in the acid (H+) form to yield [H3O+]2[B12Br12],

[0039] [H3O+]2[B12F12] • 2H2O:A commercial solution of [H3O+]2[B12F12] in water (48-52 wt.%) is concentrated under vacuum at a temperature of 120°C to give a white solid.Water is removed from an aqueous solution of [H3O+]2[B12H12] to yield [H3O+]2[B12H12] • 4H2O as a dry powder.

[0041] [H3O+]2[B12Cl11OH] • 4H2O:An aqueous solution of Cs2[B12H12] is reacted with dilute sulfuric acid to produce Cs2[B12H11OH], which is further reacted with NaOCI and HCI to produce Cs2[B12Cl11OH]. The reaction is quenched with sodium sulfite, and the product recovered and recrystallized. The Cs2[B12Cl11OH] is converted to [H3O+]2[B12Cl11OH] by stirring with a strong acid cation exchange resin in the acid form.

[0042] [H3O+]2[B12Cl11Br] • 4H2O:An aqueous solution of Cs2[B^2H^2] is reacted with tetrabutylammonium bromide (NBu4Br) to produce [NBu4]2[B12H12], The [NBu4]2[B12H12] is dissolved in acetonitrile and reacted with N-bromosuccinimide at -15°C to produce [NBu4]2[B12H11Br], The [NBu4]2[B12H11Br] is dissolved in methanol. Sodium tetraphenylborate is added to produce Na2[B12H11Br] with precipitation of [NBu4][BPh4], The Na2[B12H11Br] is recovered,suspended in water. Concentrated HCI is then added, followed by a solution of NaOCI in water. The resulting reaction mixture is heated overnight to produce Na2[B12Cl11Br] in aqueous solution. Triethylamine hydrochloride is added to produce [Et3NH]2[B12Cl11Br] which is then converted to the hydronium salt by stirring with a strong acid cation exchange resin in the acid form.^a2®10^10 ‘s combined with water and then concentrated HCI. A 6% NaOCI solution is added and the mixture heated to reflux overnight. Triethylammonium chloride is added. A white precipitate forms and is isolated by filtration and dried. The precipitate is dissolved in methanol and combined with a strong acid ion exchange resin in the hydrogen form overnight. The resin is removed by filtration and to the filtrate is added an aqueous CsOH solution, forming a white precipitate which is isolated by filtration. The solids are taken up in a 1: 1 by volume mixture of water and CH3CN and again combined with the ion exchange resin. After standing overnight, the mixture is filtered and the water removed under vacuum to (H3O)2B10Cl10).

[0044] [H3O+]2[B10Br10]:^a2®10^10 ‘scombined with water and concentrated HBr. NaOCI solution is added and the resulting mixture refluxed for 3 hours. The mixture is cooled and charged with triethylammonium chloride to precipitate a white solid. The solid is recovered by filtration, dissolved in methanol and combined with a strong acid ion exchange resin in the hydrogen form. The product is recovered and treated with a slight molar excess of CsOH to produce a white precipitate which is again combined with the ion exchange resin and then dried to produce the product.Cs2B12H12(100mg, 0.26 mmol) is combined with acetic acid and iodine and the resulting mixture is heated to 230C for 2.5h, followed by quenching with Na2SO3. The mixture is filtered and combined with tetrabutylammonium bromide. The resulting solid is collected by filtration. The solid is dissolved in a methyl cyanide / water mixture and stirred with for 2 hours with a strong acid ion exchange resin in the hydrogen form and then dried to produce (H3O)2B12I12.Semi-Batch Polymerization Procedure

[0046] Examples 1 to 11 and Comparative Samples A and B are performed in semi-batch pressure reactor is charged with 45 grams of initiator (sorbitol in Ex. 4, glycerin in all othercases) and solid catalyst in an amount as indicated in Table 1. The reactor is purged with nitrogen and heated to 160°C with stirring. Propylene oxide is fed into the reactor at a rate that maintains 30 psi (207 kPa) of PO partial pressure. The rate of consumption of propylene oxide per mole of catalyst is calculated from the feed rate and PO partial pressure. Upon completion of monomer feed, the reaction is allowed to digest by maintaining the temperature at 160°C for 2 to 16 hours and then cooled to 50°C under nitrogen purge. After purging at 50°C for 10 min, the product is collected.

[0047] The resulting products are analyzed for molecular weight and polydispersity (Mw / Mn) by gel permeation chromatography against a polyether standards. Primary hydroxyl content is determined by functionalizing the product with trifluoroacetic anhydride and evaluating the resulting product byNMR spectroscopy, per a standard method such as ASTM D-4273.

[0048] Examples 1 to 12 and Comparative Samples A and BTABLE 1‘Comparative.10n a molar basis of catalyst.^Zinc hexacyanocobaltate catalyst complex.^Sorbitol initiator; all other experiments use glycerol as the starter.^Based on the weight of the starter. ND — not determined.

[0049] As shown by the data in Table 1, the polyhedral catalysts provide a reaction rate that is about 3 to 4 orders of magnitude faster than provided by the potassium hydride, when used at levels of 250 to 500 ppm. As shown in Example 3, reaction rates slow considerably when the catalyst level is reduced to 100 ppm, but even in this case the reaction rate is 200 times that provided by KH. The products have desirably low polydispersities. Notably, the products have very high proportions of primary hydroxyl groups.

[0050] Example 12 (Ex. 12) is performed in a Parallel Pressure Reactor at 160°C using the general polymerization procedure described in WO 2021 / 154780. The initiator is a 700 molecular weight propoxylated glycerol and the catalyst isat aconcentration of 1600 ppm based on the weight of the starter. A 597 number average molecular weight product having a polydispersity of 1.49 is obtained.

[0051] The invention of this disclosure has been described in an illustrative manner, and it was to be understood that the terminology which has been used was intended to be words of description rather than of limitation. Obviously, many modifications and variations of the present invention are possible considering the above teachings. The invention may be practiced otherwise than as specifically described.

Claims

CLAIMSWhat is claimed is:

1. A method for producing an alkoxylate, the method comprising:combining (1) a polyhedral borate, (2) at least one starter, and (3) at least one alkylene oxide; andsubjecting the resulting combination to alkoxylation conditions such that the starter and alkylene oxide react to produce an alkoxylate;wherein the polyhedral borate comprises[Cat+]n[B12XuYv]n- and / or [Cat+]m[B10XwYz]m-,whereCat+is a proton or a protonated neutral molecule, each X is independently selected from hydrogen, halogen; C-^Q hydrocarbyl, which is optionally substituted with halogen; -OH, -OR -SH, -SR cyanide, nitrite or triflate, each Y is independently selected from NH3,cyclic thioether, cyclic dithioether, O(R^)2, cyclic ether, cyclic diether, O=S(R^)2, S(O)2(R^)2, and O=P(R1)3, where each R^ is independently C-|_35 hydrocarbyl, which is optionally substituted with halogen, v is 0 or 1, n is (2-v), u is (12-v), z is 0 or 1, m is (2-z), and w is (10-z).

2. The method of claim 1, wherein each X is independently hydrogen, halogen or hydroxyl.

3. The method of claim 1, wherein the polyhedral borate is one or more of [Cat+]2[B12H12]2-- ZH2O, [Cat+]2[B12F12]2- • ZH2O, [Cat+]2[B12CI12]2- • ZH2O, [Cat+]2[B12Br12]2- • ZH2O, ZH2O, [Cat+]2[B12I12]2' • ZH2O,[Cat+]2[B12(OH)12]2- • ZH2O, [Cat+]2[B12HaF12.a]2- • ZH2O,[Cat+]2[B12HaCI12.a]2- • ZH2O, [Cat+]2[B12HaBr12.a]2- • ZH2O, [Cat+]2[B12Hal12.a]2- • ZH2O, [Cat+]2[B12Ha(OH)12.a]2- • ZH2O, [Cat+]2[B12FaCI12.a]2- • ZH2O, [Cat+]2[B12FaBr12.a]2- • ZH2O, [Cat+]2[B12Fal12.a]2- • ZH2O, [Cat+]2[B12Fa(OH)12.a]2- • ZH2O,[Cat+]2[B12ClaBr12.a]2- • ZH2O, [Cat+]2[B12Clal12.a]2- • ZH2O, [Cat+]2[B12Cla(OH)12.a]2- • ZH2O, [Cat+]2[B12Bral12.a]2- • ZH2O, [Cat+]2[B12Bra(OH)12.a]2- • ZH2O, [Cat+]2[B12la(OH)12.a]2- • ZH2O, [Cat+]2[B10H10]2- • ZH2O, [Cat+]2[B10F10]2- • ZH2O, [Cat+]2[B10CI10]2- • ZH2O, [Cat+]2[B10Br10]2- • ZH2O, [Cat+]2[B10l10]2- • ZH2O, [Cat+]2[B10(OH)10]2- • ZH2O, [Cat+]2[B10HbF10.b]2- • ZH2O, [Cat+]2[B10HbCI10.b]2- • ZH2O, [Cat+]2[B10HbBr10.b]2- • ZH2O, [Cat+]2[B10Hbl10.b]2- • ZH2O, [Cat+]2[B10Hb(OH)10.b]2- • ZH2O, [Cat+]2[B10FbCI10.b]2- • ZH2O, [Cat+]2[B10FbBr10.b]2- • ZH2O, [Cat+]2[B10Fbl10.b]2- • ZH2O, [Cat+]2[B10Fb(OH)10.b]2- • ZH2O, [Cat+]2[B10ClbBr10.b]2- • ZH2O, [Cat+]2[B10Clbl10.b]2- • ZH2O, [Cat+]2[B10Clb(OH)10.b]2- • ZH2O, [Cat+]2[B10Brbl10.b]2- • ZH2O, [Cat+]2[B10Brb(OH)10.b]2- • ZH2O,each a is 1 to 11, each b is 1 to 9, and each Z is 0 to 12.

4. The method of claim 1 wherein the polyhedral borate is one or more of[Cat+][B12l11(SR12)r • ZH2O, [Cat+][B10H9(NR13)J- • ZH2O,[Cat+][B10F9(NR13)]- • ZH2O, [Cat+][B10CI9(NR13)]- • ZH2O,[Cat+][B10Br9(NR13)J- • ZH2O, [Cat+][B10l9(NR13)J- • ZH2O,[Cat+][B10H9(PR13)r • ZH2O, [Cat+][B10F9(PR13)]- • ZH2O,[Cat+][B10CI9(PR13)r • ZH2O, [Cat+][B10Br9(PR13)J- • ZH2O,[Cat+][B10l9(PR13)J- • ZH2O, [Cat+][B10H9(SR12)J- • ZH2O,[Cat+][B10F9(SR12)J- • ZH2O, [Cat+][B10CI9(SR12)J- • ZH2O,[Cat+][B10Br9(SR12)J- • ZH2O, [Cat+][B10I9(SR12)]-• ZH2O, where each Z is 0 to 12.

5. The method of any one preceding claim, wherein [Cat+] is selected from the group consisting of hydronium, a protonated alcohol, a protonated ether, a protonated arene, a protonated alkene, a protonated thiol, and a protonated thiol ether.

6. The method of claim 5, wherein [Cat+] is hydronium.

7. The method of any one preceding claim, wherein the polyhedral borate is one or more of [H3O+]2[B12H12]2' • ZH2O, [H3O+]2[B12F12]2' • ZH2O,[H3O+]2[B12CI12]2- • ZH2O, [H3O+]2[B12Br12]2- • ZH2O, [H3O+]2[B12I12]2- • ZH2O,[H3O+]2[B10H10]2- • ZH2O, [H3O+]2[B10CI10]2- • ZH2O, and [H3O+]2[B10Br10]2- • ZH2O.

8. The method of any one preceding claim, wherein the starter has 1 to 12 primary, secondary, or tertiary hydroxyl or thiol groups.

9. The method of claim 8, wherein the starter has 2 to 8 hydroxyl groups and a hydroxyl equivalent weight of 30 to 250 g / equivalent.

10. The method of any one preceding claim, wherein the alkylene oxide is propylene oxide, ethylene oxide, or a mixture of at least 50% by weight propylene oxide and correspondingly up to 50% by weight ethylene oxide.

11. The method of any one preceding claim, wherein the combination subjected to alkoxylation conditions contains 100 to 5,000 parts by weight of the polyhedral borate per million parts by weight of the starter.

12. The method of any one preceding claim, wherein the alkoxylation conditions include a temperature of from 80°C to 190°C.

13. The method of any one preceding claim, wherein the alkoxylation conditions are continued until 1 to 5 moles of the alkylene oxide are added to the starter per equivalent of hydroxyl or thiol group on the starter.

14. The method of any one preceding claim, wherein the alkylene oxide is propylene oxide and at least 50% of the hydroxyl groups of the alkoxylate are primary hydroxyl groups.

Images