Semibatch alkylene oxide polymerization process using Lewis acid catalysts.

Abstract

The polyether polyols are prepared by polymerizing one or more alkylene oxides in the presence of a Lewis acid polymerization catalyst. The reaction is carried out by forming a starting reaction mixture containing an initiator and a catalyst. The alkylene oxide and additional catalyst are then added simultaneously, sequentially, and separately under reaction conditions including a temperature of at least 75°C.

Description

[Technical field]

[0001] The present invention relates to a semi-batch process for polymerizing alkylene oxide.

[0002] Polyethers are produced in very large quantities on earth. They are used, among other things, to produce polyurethanes, such as rigid, flexible, semi-flexible or viscoelastic foams.

[0003] Polyethers can be made by polymerizing alkylene oxides in the presence of an initiator, which has one or more functional groups, typically hydroxyl, primary amino, or secondary amine groups, that allow the alkylene oxide to participate in a ring-opening reaction, whereby an oxyalkylene unit is added to the chain, generating a new terminal hydroxyl group to which the next alkylene oxide molecule can be added to extend the polyether chain.

[0004] Alkylene oxide polymerization can be carried out in a batch, continuous, or semi-batch process. A semi-batch process is characterized in that the alkylene oxide is fed to a reaction vessel under reaction conditions over a period of time without removing the product until polymerization is complete. Semi-batch is sometimes advantageous because it can produce products having narrow molecular weight distributions.

[0005] Alkylene oxide polymerization reactions are catalyzed. The main catalysts are alkali metal hydroxides (especially potassium hydroxide) and so-called "double metal cyanide" catalysts, typified by zinc hexacyanocobaltate complexes. Each of these has advantages and disadvantages. Alkali metal hydroxide catalysts are inexpensive and can be used to polymerize both of the two main alkylene oxides used in polyether production (1,2-propylene oxide and ethylene oxide), and therefore can be used to produce a wide range of polyether products. A disadvantage of alkali metal hydroxide catalysts is that the product must be neutralized and catalyst residues carefully removed. This adds significant production costs. Another disadvantage is that strongly basic conditions catalyze the isomerization of 1,2-propylene oxide to propenyl alcohol and / or allyl alcohol, which can each be alkoxylated to produce undesirable monofunctional species.

[0006] Double metal cyanide catalysts are useful at very low concentrations, which may leave catalyst residues in the product, avoiding the neutralization and / or catalyst removal steps and associated costs. They also do not promote 1,2-propylene oxide isomerization. However, they have difficulty polymerizing ethylene oxide, and when producing ethylene oxide-capped polyethers, a capping step must usually be performed with an alkali metal catalyst. This negates many of the advantages of using double metal cyanide catalysts.

[0007] The third class of alkylene oxide polymerization catalysts are Lewis acids. Lewis acid catalysts have the advantage of promoting both head-to-head and head-to-tail addition of 1,2-propylene oxide. This allows the production of polyethers with reasonably high primary hydroxyl content by polymerizing 1,2-propylene oxide. This is advantageous when ethylene oxide is not readily available or when highly reactive polyols with low hydrophilicity are required. Lewis acids tend to deactivate rapidly and often catalyze the undesired reaction of 1,2-propylene oxide to propionaldehyde.

[0008] WO 2019 / 055727, WO 2018 / 055731, WO 2019 / 055734 and WO 2019 / 055740 describe a class of boron, aluminum, indium, bismuth or erbium-containing fluoroalkyl-substituted Lewis acids for use as alkylene oxide polymerization catalysts. In the examples, these patent publications describe the production of polyols with molecular weights up to about 1000 at a polymerization temperature of 90° C. Higher molecular weight polyols are produced at lower polymerization temperatures of 55° C. These polymerization temperatures are too low for industrial-scale polyether polyol production because the polymerization reaction is highly exothermic and it is impractical to control an industrial-scale polymerization plant to such low temperatures.

[0009] The present invention is a process for the polymerization of alkylene oxide comprising the steps of: a) forming a starting reaction mixture, the reaction mixture having a temperature of at least 75° C., comprising: 1) an initiator having at least one functional group capable of being oxyalkylated; and 2) at least one Lewis acid alkylene oxide polymerization catalyst; b) while maintaining a temperature of at least 75°C, C) continuously and simultaneously adding in a separate stream to the starting reaction mixture, 3) at least one alkylene oxide and 4) additional Lewis acid alkylene oxide polymerization catalyst, combining the separate streams with the starting reaction mixture and polymerizing the alkylene oxide to produce a polyether corresponding to the reaction of the at least one alkylene oxide with the initiator, wherein step b) is performed without removing the polyether product; and optionally c) discontinuing the simultaneous addition of the alkylene oxide and the additional Lewis acid alkylene oxide polymerization catalyst stream; d) after step c), optionally heating the reaction mixture to at least 75° C. to continue polymerization of any alkylene oxide remaining in the reaction mixture at the end of step b); e) recovering the polyether product.

[0010] The process of the present invention provides a route to efficiently alkoxylate initiators at commercially acceptable operating temperatures using Lewis acid alkoxylation catalysts.

[0011] Initiators are compounds that have one or more functional groups that can be alkoxylated.Examples of such functional groups include primary, secondary or tertiary hydroxyl groups, primary or secondary amino groups, mercaptan and carboxylic acid groups.Initiators that have one or more, especially two or more hydroxyl groups, but do not have primary amino, secondary amino, mercaptan or carboxylic acid groups (or other functional groups that can be alkoxylated) are particularly interesting for preparing polyether alcohols that are useful for polyurethane applications.

[0012] The molecular weight of the initiator is not critical and can range from 18 (for water) to 10,000 g / mol or more. For purposes of the present invention, molecular weight is the formula molecular weight for compounds having a formula molecular weight of up to 250 g / mol, otherwise it is the number average molecular weight. Initiators of particular interest have a molecular weight of 60 g / mol to 1000 g / mol.

[0013] Specific examples of useful hydroxyl-containing initiators include allyl alcohol, propenyl alcohol, water, ethylene glycol, diethylene glycol, triethylene glycol, 1,2- and / or 1,3-propylene glycol, dipropylene glycol, tripropylene glycol, pentaerythritol, erythritol, cyclohexanedimethanol, glycerin, trimethylolpropane, trimethylolethane, triethanolamine, triisopropanolamine, sorbitol and sucrose, as well as any one or more alkoxylates having a number average molecular weight of up to 10,000 g / mol, especially up to 1,000 g / mol.

[0014] Particularly preferred initiators are polyether polyols having 2 to 8 hydroxyl groups and number average molecular weights of 250 to 1,000 g / mol, in particular 300 to 800 g / mol.

[0015] The catalyst is a Lewis acid, which means a compound that can accept an electron pair.

[0016] Among the useful Lewis acid catalysts are those of the general formula M(R 1 )1(R 2 )1(R 3 )1(R 4 ) 0又は1 (I) where M is boron, aluminum, indium, bismuth or erbium; 1 is a fluoroalkyl-substituted phenyl group, R 2 and R 3 are each a fluoroalkyl-substituted phenyl group, a fluoro-substituted phenyl group, a chloro-substituted phenyl group, or a fluoro- and chloro-substituted phenyl group. 4is a functional group or a functional polymer group. M in the general formula may be present as a metal salt ion or as an integrally bonded part of the formula. Suitable such catalysts and methods for preparing them are described, for example, in WO 2019 / 055727, WO 2019 / 055731, WO 2019 / 055734 and WO 2019 / 055740.

[0017] Fluoroalkyl-substituted phenyl group R 1 At least one fluoroalkyl substituent of may be, for example, a fluorine-substituted alkyl group having 1 to 5 carbon atoms. A fluorine-substituted methyl group is preferred. The alkyl group includes at least one fluorine substituent and can have any number of fluorine substituents up to perfluorination. Preferred fluoroalkyl substituents include the -CF3 moiety. In some embodiments, the fluoroalkyl substituent is -CF3.

[0018] Fluoroalkyl-substituted phenyl group R 1 can be substituted with 1 to 5 fluoroalkyl groups. The fluoroalkyl groups can occupy any position on the phenyl ring. In some embodiments, R 1 The group is substituted with two fluoroalkyl groups, which may be located at the 2 and 5 carbons or the 3 and 5 carbons. In certain embodiments, the fluoroalkyl-substituted phenyl group R 1 is 2,5- or 3,5-bis(trifluoromethyl)phenyl.

[0019] R 1 may be substituted to include, in addition to at least one fluoroalkyl group, other groups, such as fluorine and / or chlorine atoms replacing at least one hydrogen of the phenyl group.

[0020] R 2 and R 3 is a fluoroalkyl-substituted phenyl group, R 1 As explained above. R 2 and R 3is R 1 Alternatively, R 2 and R 3 At least one of the 1 Different from. 2 and / or R 3 Instead of or in addition to being fluoroalkyl substituted, the phenyl group R may be fluoro- and / or chloro-substituted. 2 or R 3 R may be substituted with 1 to 5 fluoroalkyl, fluorine and / or chlorine atoms. 2 and examples of R3 groups, in addition to 2,5- or 3,5-bis(trifluoromethyl)phenyl, include: [ka]

[0021] Any R 4 For the functional group or functional polymer group, the functional group may be a Lewis base that complexes with a Lewis acid catalyst. By "functional group or functional polymer group" is meant a molecule that contains at least one of water, an alcohol group, an alkoxy group (examples include linear or branched ethers and cyclic ethers), a ketone group, an ester group, an organosilane group, an organosiloxane group, an oxime group, and substituted analogs of any of these groups. Each of the molecules that contain the alcohol, linear or branched ether, cyclic ether, ketone, ester, alkoxy, organosilane, organosiloxane, and oxime groups may contain 2 to 20 carbon atoms, 2 to 12 carbon atoms, 2 to 8 carbon atoms, or 3 to 6 carbon atoms.

[0022] In some embodiments, the functional group or functional polymer group has the formula (YOH): n where O is oxygen, H is hydrogen, Y is H or an alkyl group, and n is an integer (eg, an integer from 1 to 100).

[0023] Other suitable R 4Groups include diethyl ether, cyclopentyl methyl ether, methyl tertiary butyl ether, tetrahydrofuran, tetrahydropyran, 1,4-dioxane, acetone, methyl isopropyl ketone, isopropyl acetate, and isobutyl acetate.

[0024] Examples of suitable Lewis acid catalysts include (2,5-bis(trifluoromethyl)phenyl)bis(3,5-bis(trifluoromethyl)phenyl)borane, bis(2,5-bis(trifluoromethyl)phenyl)(3,5-bis(trifluoromethyl)phenyl)borane, bis(3,5-bis(trifluoromethyl)phenyl)(2,3,5,6-tetrafluoro-4-(trifluoromethyl)phenyl)borane, bis(3,5-bis(trifluoromethyl)phenyl)(pentachlorophenyl)borane, and tetrahydrofuran (THF) adduct of bis(3,5-bis(trifluoromethyl)phenyl)(2,4,6-trifluorophenyl)borane. Adducts such as bis(3,5-bis(trifluoromethyl)phenyl)(2,4,6-trifluorophenyl)borane and its THF adduct are of particular interest herein because they tend to deactivate more rapidly at high temperatures than many of the other compounds represented by structure (I) above.

[0025] The alkylene oxide is one or more monoepoxide compounds such as ethylene oxide, 1,2-propylene oxide, 1,2- or 2,3-butylene oxide, 1,2-hexene oxide, styrene oxide, cyclohexane oxide, etc. Any of these may be the only alkylene oxide polymerized in the process. If desired, mixtures of any two or more can be polymerized. Two or more alkylene oxides can be polymerized sequentially in the process in any order. In some embodiments, ethylene oxide, 1,2-propylene oxide, or 1,2-butylene oxide are homopolymerized. In other embodiments, 1,2-propylene oxide is randomly polymerized with ethylene oxide and / or 1,2-butylene oxide by adding a mixture of oxides during step b). In other embodiments, ethylene oxide is randomly polymerized with 1,2-butylene oxide by adding a mixture of oxides during step b). In yet other embodiments, block copolymers of 1,2-propylene oxide and ethylene oxide or 1,2-butylene oxide, or block copolymers of ethylene oxide and 1,2-butylene oxide are prepared by sequential addition of the oxides in step b) or by performing step b) multiple times using different oxides in two or more runs of step b).

[0026] The process of the invention is of the type commonly referred to as a "semi-batch" process in which a starting reaction mixture is formed, reaction conditions are established, and additional components are added to and combined with the starting reaction mixture under reaction conditions that are preferably steady state conditions, where the starting reaction mixture comprises at least an initiator and a Lewis acid alkylene oxide polymerization catalyst, the additional components comprise separately added alkylene oxide and additional Lewis acid alkylene oxide polymerization catalyst, and the reaction conditions comprise a temperature of at least 100°C. The pressure can be subatmospheric, atmospheric, or superatmospheric, with superatmospheric pressure generally being preferred.

[0027] A starting reaction mixture comprising an initiator and a Lewis acid alkylene oxide polymerization catalyst is formed in step a) of the process and is brought to a temperature of at least 75°C. This can be done by mixing the ingredients in any order. The ingredients can be heated before, during or after they are mixed to form the starting reaction mixture. The temperature can be at least 90°C, at least 100°C, 110°C, at least 115°C or at least 120°C. In some embodiments, the temperature is at most 180°C, at most 150°C or at most 140°C.

[0028] The catalyst may be dissolved in a suitable solvent to facilitate the formation of the starting reaction mixture. This is generally preferred when the catalyst is solid or highly viscous under the conditions in which it is added to the reaction. Preferred solvents include, for example, allyl alcohol, propenyl alcohol, water, ethylene glycol, diethylene glycol, triethylene glycol, 1,2- and / or 1,3-propylene glycol, dipropylene glycol, tripropylene glycol, pentaerythritol, erythritol, cyclohexanedimethanol, glycerin, and 1,6-hexanediol, as well as any one or more of the starting compounds described above, including alkoxylates having a number average molecular weight of up to 10,000 g / mol, particularly up to 1,000 g / mol, or up to 500 g / mol. Other useful solvents include monoalcohols such as 1-butanol, 1-hexanol, 1-octanol, 1-decanol, polyether monools having number average molecular weights up to 10,000 g / mol, particularly up to 1,000 g / mol, or up to 500 g / mol, hydrocarbons such as toluene, various glycol mono- and diethers, and various glycol mono- and diesters.The catalyst solution may contain, for example, 5 to 50 wt%, 10 to 50 wt%, or 10 to 30 wt% active catalyst.

[0029] The amount of Lewis acid alkylene oxide polymerization catalyst combined with the initiator to form the starting reaction mixture can be, for example, at least 50 parts by weight, at least 100 parts by weight, at least 200 parts by weight, at least 400 parts by weight, or at least 500 parts by weight per million parts by weight of initiator, and can be, for example, up to 5000 parts by weight, up to 3000 parts by weight, up to 2000 parts by weight, up to 1500 parts by weight, or up to 1000 parts by weight per million parts by weight of initiator.

[0030] The starting reaction mixture may contain some initial amount of alkylene oxide before the start of step b), but the presence of such initial amount of alkylene oxide is optional and the starting reaction mixture may contain no alkylene oxide before the start of step b).If alkylene oxide is present in the starting reaction mixture before step b), its mass is preferably less than or equal to the mass of the initiator, more preferably less than or equal to half or a quarter of the mass of the initiator.

[0031] In step b) of the process, separate streams of alkylene oxide and additional Lewis acid alkylene oxide polymerization catalyst are added to and combined with the reaction mixture. The separate streams are added continuously and simultaneously. The start of step b) coincides with the time when the separate alkylene oxide and additional Lewis acid alkylene oxide polymerization catalyst streams begin to be added simultaneously. Step b) ends when the simultaneous addition is stopped. The addition of these streams is carried out while maintaining a temperature of at least 75°C. The temperature during this step can be as described above for the starting reaction mixture. As previously mentioned, the pressure can be subatmospheric, atmospheric or superatmospheric. The temperature and pressure conditions described above represent polymerization conditions. Thus, the alkylene oxide is at least partially polymerized during step b) to produce a polyether.

[0032] In step b), the alkylene oxide and Lewis acid alkylene oxide polymerization catalyst may be added over a period of, for example, 10 minutes to 40 hours or more. Preferred times are at least 30 minutes, at least 60 minutes, or at least 90 minutes. The period of addition in step b) is, in some embodiments, up to 20 hours, up to 15 hours, up to 8 hours, up to 6 hours, up to 4 hours, or up to 3 hours. When step b) is performed multiple times, the addition time for each time may be as described above.

[0033] In some embodiments, the rate of addition of the stream during optional step b) is selected to maintain the amount of unreacted alkylene oxide (URO) in the reaction mixture at or below 10 wt.%, preferably at or below 6 wt.%, at or below 4 wt.%, or at or below 2 wt.%, based on the total weight of the reaction mixture at any time measured. In particularly preferred embodiments, URO is maintained at 0.25-4%, especially 0.25-2%, at all times during step b) of the process.

[0034] In step b), the relative rates of addition of the streams may, in some embodiments, be such that at least one alkylene oxide is added at a rate R ao g / min, and at least one Lewis acid alkylene oxide polymerization catalyst is added at 0.0001 to 0.01 R ao (active catalyst basis). The at least one Lewis acid alkylene oxide polymerization catalyst may be added at a rate of, for example, at least 0.005 R ao , at least 0.0025R ao , at least 0.004R ao , or at least 0.005R ao For example, the addition rate may be up to 0.0025R ao , 0.0015R ao , max. 0.001R ao , or up to 0.0008R aoThese relative addition rates are applicable both to the average relative addition rate during the entire step b) and to the instantaneous relative addition rate at any particular time during step b). The relative rates of addition of the streams may or may not be kept constant during step b). Thus, the average relative addition rate may differ from any instantaneous relative addition rate.

[0035] The total amount of Lewis acid alkylene oxide polymerization catalyst added to the reaction mixture during the process may be, for example, 50 to 3000 or 200 to 3000 parts by weight per million parts by weight of the combined weight of the initiator and the at least one alkylene oxide. The weight of Lewis acid alkylene oxide polymerization catalyst includes that added in step a), each step b), or otherwise. The weights of each of the initiator and the at least one alkylene oxide include all of the initiator and alkylene oxide charged to the reaction mixture during the process, including that added in step a), each step b), or otherwise.

[0036] If desired, additional initiator may be added during optional step b).

[0037] After step b) (or after each step b), if more than one is performed, the simultaneous addition of the alkylene oxide and Lewis acid alkylene oxide polymerization catalyst streams is discontinued. It is within the scope of the invention to continue the separate addition of one or both of these steam streams after any step b).

[0038] After step c), the reaction mixture is optionally heated to at least 75° C. (step d)) to continue the polymerization of the alkylene oxide remaining in the reaction mixture at the end of step b). Temperature and pressure conditions as described for step b) are applicable for this step. It is preferred to carry out this optional heating step until the URO is reduced to 1 wt. % or less, more preferably 0.5 wt. % or less. It is preferred not to add any additional catalyst, alkylene oxide or initiator during optional step d).

[0039] As mentioned above, steps b) and c) may be carried out multiple times, and optionally and preferably step d) may be inserted between step c) and any subsequent step b). As mentioned above, the alkylene oxide(s) used in the different steps b) may be the same or different. If multiple steps b) and c) are carried out, multiple steps d) may be carried out.

[0040] This process produces a polyether product formed by polymerizing alkylene oxide(s) to initiator(s). The polyether product has a higher molecular weight than the initiator(s). The polyether product can have, for example, a number average molecular weight (by gel permeation chromatography (GPC) against polyether standards) of 800 g / mol to 12000 g / mol or more. In certain embodiments, the number average molecular weight of the polyether product can be at least 1000, at least 1200, at least 1500, at least 1800, or at least 2000 g / mol, and can be, for example, up to 8,000, up to 6,000, or up to 5,000 g / mol. The polyether product preferably has at least 1, more preferably 2-8 hydroxyl groups, and in such case may have a hydroxyl equivalent weight of at least 200, at least 330, at least 400, at least 500, at least 750, or at least 900, and up to 6000, up to 4000, up to 3000, or up to 2500 g / equivalent (by titration to determine the corresponding hydroxyl number in mg KOH / g according to ASTM D4274-21, or equivalent, followed by conversion to equivalents using the relationship equivalent weight = 56100 ÷ hydroxyl number). The polyether product may have a polydispersity (weight average molecular weight divided by number average molecular weight, in each case determined by GPC against polyether standards) of 1.175 or less. The polydispersity can be, for example, from 1.00 to 1.16, from 1.00 to 1.12, from 1.00 to 1.10, from 1.00 to 1.08, or from 1.00 to 1.06.

[0041] The number average molecular weight of the polyether product may be, for example, 2 to 200 times the number average molecular weight of the initiator(s). In certain embodiments, the number average molecular weight of the polyether product may be up to 100 times, up to 50 times, up to 25 times, up to 15 times, or up to 10 times the number average molecular weight of the initiator.

[0042] The product is recovered by removal from the reaction vessel(s) upon completion of the polymerization. Various processing steps may be performed before or after recovering the polyether product. Unreacted alkylene oxide and / or initiator may be separated from the product. Catalyst residues may be separated from the product. Volatile residues and / or by-products may be removed. One or more antioxidants or other preservatives may be added to the product. The product may be blended with one or more other polyethers, with water, and / or with other materials that may be useful in downstream applications in which the polyether is used.

[0043] In some embodiments, the polyether product is a homopolymer of 1,2-propylene oxide in which at least 40%, or at least 45% of the hydroxyl groups of the polyether product are primary. In such embodiments, up to 85%, up to 80%, up to 70%, or up to 65% of the hydroxyl groups may be primary. The primary hydroxyl content is determined by the trifluoroacetic anhydride derivative of the polyol. 9 It can be determined by F NMR analysis.

[0044] The polyether product preferably contains at most a small amount of acetals. Acetals can be formed in some alkylene oxide polymerization processes through the formation and subsequent reaction of aldehyde-containing species, for example as described by Raghuraman et al. in Macromolecules 2016, 49(18), pp. 6790-6798. Hydroxyl-containing polymers of 1,2-propylene oxide preferably contain up to 5 mol % acetals, more preferably 2 mol % or less, 1.5 mol % or less, or 1 mol % or less acetals, based on the moles of carbon atoms in the polymer. The acetal content can be determined by the inverse gated method. 13 It can be determined by C NMR spectroscopy. A suitable procedure is as follows: Samples are prepared as ∼90% solutions in DMSO-d6 in 10 mm NMR tubes. 13 C NMR data are acquired using a Bruker Avance 400-MHz spectrometer equipped with a cryoprobe or equivalent using at least 64 temporal scans and a relaxation delay of 30 seconds (optimized for quantitative measurements). Acquisition is performed using a spectral width of 25,000 Hz and a file size of 65,000 data points. The relative moles of acetal species are measured by integrating the area under the resonance from the acetal carbon. Mole % acetal = 100% x relative moles of acetal carbon ÷ sum of the relative moles of all carbon species in the spectrum.

[0045] The polyether products are useful in the production of polyurethanes and other applications where other polyethers of similar molecular weight are hydroxyl functional. The polyether products can be reacted with polyisocyanates to produce a wide variety of polyurethane polymers including, for example, rigid polyurethane and / or polyurethane-isocyanurate foams, flexible polyurethane foams, viscoelastic polyurethane foams, microcellular polyurethane foams, noncellular polyurethane elastomers, noncellular polymers, polyurethane coatings, polyurethane sealants, polyurethane adhesives, and the like.

[0046] The following examples are provided to illustrate the invention but are not intended to limit the scope of the invention. All parts and percentages are by weight unless otherwise indicated.

[0047] Examples 1 to 3 and Comparative Samples A and B In the following examples, the catalyst in all cases is the tetrahydrofuran adduct of bis(3,5-bis(trifluoromethyl)phenyl)(2,4,6-trifluorophenyl)borane. This catalyst corresponds to catalyst 6 of WO 2019 / 055727 and is suitably prepared as described for catalyst 6 of WO 2019 / 055727. The catalyst solution is 90% by weight of 425M tetrahydrofuran adduct. n The catalyst is contained at 10% by weight in poly(propylene oxide) diol.

[0048] The thermal stability of this catalyst is evaluated as follows: Poly(propylene glycol) (425 g / mol) is sparged with dry nitrogen at 110 °C for 18 h. In an oxygen-free wet box, degassed water (50 μL) is added to 10 mL of poly(propylene glycol) in a 20 mL glass vial. 664 μL of the resulting wet poly(propylene glycol) is combined with 35 mg of catalyst in an 8 mL glass vial and stirred vigorously for 15 min. The solution is transferred to a 5 mm NMR tube containing a sealed glass capillary holding a 10 vol. % solution of C6F6 in toluene-d8. The NMR tube is capped and sealed with electrical tape heated to 60 °C and maintained at this temperature. 19 F NMR spectra are collected on a Varian 400-MR and a Bruker Avance 500 NMR spectrometer using a standard pulse sequence of ns=32, d1=5s. Spectra are collected every 15 min for 15 h. Integrals are normalized to a C6F6 internal standard. Decomposition is calculated from the integrals of the signals corresponding to the ortho-fluorine atoms of the bis(3,5-bis(trifluoromethyl)phenyl)(2,4,6-trifluorophenyl)borane tetrahydrofuran complex. The amount of catalyst decomposition after 15 h at 60° C. is about 2.9 wt %.

[0049] When this test is repeated at 90°C, 14.5% of the catalyst decomposes after only 4 hours, and 39.6% decomposes after 15 hours. When repeated again at 120°C, 96.8% of the catalyst decomposes after 4 hours, with complete decomposition seen after 15 hours.

[0050] Comparative sample A: 270.48g of 700M n The poly(propylene oxide) triol initiator is charged to a 1.88 L stainless steel reactor along with 3.62 g of catalyst solution. This corresponds to an initial catalyst concentration of 1338 ppm relative to the product, which is considered the combined weight of initiator and alkylene oxide added. The reactor temperature is brought to 120° C. Then, at that temperature, 1,2-propylene oxide is added to the reactor at a constant feed rate of 1.66 g (2 mL) / min. The concentration of unreacted 1,2-propylene oxide (URO) is continuously monitored. The URO reaches 10 wt. % of the reaction mixture 75 minutes after the 1,2-propylene oxide addition. This URO value indicates that the added 1,2-propylene oxide did not essentially polymerize onto the initiator, likely because the catalyst was deactivated under these temperature conditions. The 1,2-propylene oxide feed is stopped at this point while maintaining the reaction temperature at 120° C. The URO did not decrease, further indicating that the catalyst was deactivated.

[0051] Comparative Sample B: 269.54 g of the initiator described in Comparative Sample A is charged to the same reactor. No initial charge of catalyst is made. The reactor contents are brought to 120° C. 1,2-propylene oxide is fed to the reactor at a constant rate of 1.66 g / min (2 mL / min) while maintaining the reactor temperature at 120° C. Starting simultaneously, catalyst solution is fed to the reactor as a separate stream at a rate of 0.018 g / min. The feed ratio is such as to provide and maintain a catalyst loading of about 1084 ppm based on the amount of 1,2-propylene oxide added. After 21 minutes, the total amount of catalyst added is about 124 ppm based on the combined weight of initiator and 1,2-propylene oxide added. After 21 minutes, the URO reaches 10 wt %, indicating that essentially no 1,2-propylene oxide has polymerized.

[0052] This experiment demonstrates that continuous feeding of catalyst alone is insufficient in a semi-batch process at 120°C.

[0053] Example 1: 260.54 g of initiator and 1.57 g of catalyst solution are charged to the same reactor as described in the comparative sample. These amounts correspond to about 602 ppm of catalyst based on initiator weight on an active basis. The reaction mixture is brought to 120° C. While maintaining that temperature, 1,2-propylene oxide is fed to the reactor at a rate of 1.66 g / min (2 mL / min). Commencing simultaneously, catalyst solution is fed to the reactor in a separate stream at a rate of 0.01 g / min (0.001 g / min active catalyst). This addition rate maintains the cumulative amount of catalyst added at about 602 ppm throughout the addition of the feed streams. The 1,2-propylene oxide and catalyst flows are continued for about 202 minutes, during which time 335.94 g of 1,2-propylene oxide (R ao = 1.663 g / min) and 2.04 g of catalyst solution (0.204 g active catalyst, addition rate = 0.0006 R ao ) is fed to the reactor. The URO remains below 2% for the entire time that the 1,2-propylene oxide and catalyst feeds are continued, indicating that the 1,2-propylene oxide is polymerizing at approximately the same rate as it is being fed to the reactor.

[0054] Once the feeds are complete, the reactor is maintained at 120°C to completely digest any remaining unreacted oxides, and the product is recovered by devolatilization and removal from the reactor. The total amount of catalyst added is about 603 ppm by weight of the final product mass. The product has a number average molecular weight of about 1600 g / mol, which represents the target molecular weight for this polymerization.

[0055] As this experiment shows, the addition of an additional charge of catalyst combined with the continuous addition of fresh catalyst simultaneously and separately from the addition of 1,2-propylene oxide achieves rapid and complete polymerization even at an operating temperature of 120°C.

[0056] Example 2: 265.60 g of initiator and 1.60 g of catalyst solution are charged to a reactor. This corresponds to an initial catalyst concentration of approximately 600 ppm. The reaction mixture is brought to 120° C. While maintaining the temperature, 1,2-propylene oxide is fed to the reactor at a rate of 1.66 g / min (2 mL / min). Starting simultaneously, catalyst solution is added as a separate stream at 0.01 g / min (0.001 g / min active catalyst, addition rate=0.0006 R ao ) to the reactor. This addition rate maintains the cumulative amount of catalyst added at about 602 ppm throughout the addition of the feed streams. Both feeds are continued for 96.5 minutes, at which point 160.19 grams of 1,2-propylene oxide and 0.097 g of catalyst have been fed to the reactor. The URO does not exceed 2% during the entire feed period.

[0057] The 1,2-propylene oxide and catalyst feeds are stopped for 10 minutes and then continued at their previous respective rates for an additional 107 minutes while the reactor temperature is held at 120° C. During this second feed period, the URO is less than 1%.

[0058] Once the feeds are complete, the reactor is maintained at 120°C to completely digest any remaining unreacted oxide, and the product is recovered by devolatilization and removal from the reactor. The cumulative amount of catalyst added reaches about 602 ppm based on the weight of initiator plus 1,2-propylene oxide added. The product has a number average molecular weight of about 1600 g / mol, which represents the target molecular weight for this polymerization.

[0059] Again, the addition of an additional charge of catalyst combined with the continuous addition of fresh catalyst simultaneously and separately from the addition of 1,2-propylene oxide achieves rapid and complete polymerization at an operating temperature of 120°C.

[0060] Example 3: 260.54 g of initiator and 1.63 g of catalyst solution are charged to the same reactor. These amounts correspond to about 602 ppm of catalyst based on initiator weight. The reaction mixture is brought to 120° C. While maintaining the temperature, a 2:1 weight ratio mixture of 1,2-propylene oxide and butylene oxide is fed to the reactor at a rate of about 1.64 g / min (2 mL / min). Starting simultaneously, catalyst solution is fed to the reactor in a separate stream at a rate of 0.01 g / min (0.001 g / min). This addition rate maintains a cumulative amount of catalyst added at about 600 ppm throughout the addition of the feed streams. The alkylene oxide and catalyst streams are continued for about 209 minutes, during which 343.2 g of alkylene oxide mixture and 2.09 g of catalyst solution are fed to the reactor. The catalyst addition rate is 0.0006 R on an activity basis. ao The URO remains below 2% for the entire time that the alkylene oxide and catalyst feeds are continued, indicating that the 1,2-propylene oxide and butylene oxide are polymerizing at approximately the same rate as they are being fed to the reactor.

[0061] Once the feeds are complete, the reactor is maintained at 120°C to completely digest any remaining unreacted oxides, and the product is recovered by devolatilization and removal from the reactor. The total amount of catalyst added is about 600 ppm by weight of the final product mass. The product has a number average molecular weight of about 1600 g / mol, which represents the target molecular weight for this polymerization.

[0062] As this experiment shows, similar results are obtained when polymerizing a mixture of 1,2-propylene oxide and butylene oxide. The low URO values ​​observed during the course of the reaction indicate that the catalyst effectively catalyzes the polymerization of butylene oxide as well as the polymerization of 1,2-propylene oxide, proving that the process of the present invention is effective in the homopolymerization of butylene oxide.

Claims

1. 1. A process for the polymerization of alkylene oxides, comprising: a) forming a starting reaction mixture at a temperature of at least 75° C. comprising: 1) an initiator having at least one functional group capable of being oxyalkylated; and 2) at least one Lewis acid alkylene oxide polymerization catalyst; b) while maintaining a temperature of at least 75°C, C) continuously and simultaneously adding to said starting reaction mixture in separate streams 3) at least one alkylene oxide and 4) additional Lewis acid alkylene oxide polymerization catalyst, combining said separate streams with said starting reaction mixture and polymerizing said alkylene oxide to produce a polyether corresponding to the reaction of said at least one alkylene oxide with said initiator, wherein step b) is performed without removing polyether product; and optionally c) discontinuing the simultaneous addition of said alkylene oxide and additional Lewis acid alkylene oxide polymerization catalyst stream; d) after step c), optionally heating the reaction mixture to at least 75°C to continue polymerization of alkylene oxide remaining in the reaction mixture at the end of step b); e) recovering the polyether product; 1. An alkylene oxide polymerization process comprising:

2. The at least one Lewis acid alkylene oxide polymerization catalyst has the structure: M(R １ ) １ (R ２ ) １ (R ３ ) １ (R ４ ) ０又は１ wherein M is boron, aluminum, indium, bismuth, or erbium; and R １ is a fluoroalkyl-substituted phenyl group, and R ２ and R ３ are each a fluoroalkyl-substituted phenyl group, a fluoro-substituted phenyl group, a chloro-substituted phenyl group, or a fluoro- and chloro-substituted phenyl group; R ４ 10. The alkylene oxide polymerization process of claim 1, wherein is a functional group or functional polymer group.

3. R １ , R ２ , and R ３ 3. The alkylene oxide polymerization process of claim 2, wherein:

4. R １ , R ２ , and R ３ 3. The alkylene oxide polymerization process of claim 2, wherein:

5. 10. The alkylene oxide polymerization process of claim 1, wherein the reaction mixture formed in step a) is formed by combining the initiator with from 50 to 2000 parts by weight of the at least one Lewis acid alkylene oxide polymerization catalyst per million parts by weight of the initiator.

6. 10. The alkylene oxide polymerization process of claim 1, wherein the reaction mixture formed in step a) is formed by combining the initiator with 100 to 1000 parts by weight of the at least one Lewis acid alkylene oxide polymerization catalyst per million parts by combined weight of the initiator and all alkylene oxide added to the reaction mixture during the alkylene oxide polymerization process.

7. During step b), the at least one alkylene oxide is reacted at a rate R ａｏ g / min, and the at least one Lewis acid alkylene oxide polymerization catalyst is added at a rate of 0.0001 to 0.001 R ａｏ 2. The alkylene oxide polymerization process of claim 1 wherein the alkylene oxide is added at a rate of

8. 2. The alkylene oxide polymerization process of claim 1, wherein the amount of the at least one Lewis acid alkylene oxide polymerization catalyst added to the reaction mixture in steps a) and b) is from 50 to 1000 parts by weight per million parts by weight of the combined weight of the initiator and the at least one alkylene oxide.

9. 2. The alkylene oxide polymerization process of claim 1, wherein steps b) and c) are repeated.

10. 10. The alkylene oxide polymerization process of any one of claims 1 to 9, wherein step b) is carried out in two or more stages, a first alkylene oxide being added in a first stage of step b) and a different alkylene oxide being added in a subsequent stage of step b).