JPS6111969B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing poly(tetramethylene ether) glycol. Poly(tetramethylene ether) glycol (PTMEG) is an important commodity in the chemical industry that is widely used in the production of polyurethanes and polyesters. It is conventionally generally prepared by reacting fluorosulfonic acid with tetrahydrofuran (THF) and then quenching the product with water. Although this process is initially satisfactory, it is not as efficient as desired due to the inability to recover and reuse the acid. Furthermore, due to the toxicity and corrosivity of used acids, their disposal is a problem. According to the present invention, THF, an acylium ion precursor and a catalyst for the polymerization reaction (which for summary purposes may be described as an alpha-afluorosulfonic acid group-containing polymer, although in reality is more complex) In the reaction mixture containing
It has been discovered that esters of PTMEG can be prepared by polymerizing THF. These esters are then treated with calcium, strontium, barium or magnesium oxides,
It can be converted to PTMEG by alcoholysis using hydroxides or alkoxides as catalysts. In the first part of the process, the nature of the catalyst allows its reuse, thereby eliminating the problem of disposal. The low solubility of the catalyst in the reactants also facilitates separation of the product from the catalyst at the end of the reaction. This low solubility also minimizes loss of catalyst as the reaction proceeds. The invention involves first bringing together the THF reaction components, acylium ion precursor, catalyst, and optionally carboxylic acid under conditions suitable for polymerization. Polymerization involves polymerization initiation, chain extension, chain transfer, redistribution,
It is believed to include the stages of polymerization termination and catalyst regeneration. It is believed that these steps occur simultaneously and competitively and proceed as shown in the reaction scheme below. In the reaction scheme below, carboxylic acid anhydride is used as the acylium ion precursor for illustrative purposes. Polymerization starts chain extension chain transfer redistribution Polymerization stop catalyst regeneration In these schemes, R is hydrogen or a hydrocarbon group, preferably an alkyl group having 1 to 36 carbon atoms, NfSO ₃ H represents the catalyst, and 〓〓 represents poly(tetramethylene ether). Represents a chain. When the reaction is complete, the catalyst can be separated from the reactants and reused. The THF used as a reaction component may be any commercially available THF. It preferably has a water content of about 0.001% by weight or less, a peroxide content of about 0.002% by weight or less, and it preferably has an antioxidant such as butyl to prevent the formation of undesirable by-products or colorants. Contains oxidized hydroxytoluene. If desired, an alkyltetrahydrofuran copolymerizable with THF can be used as a co-reactant in an amount of 0.1 to 50% by weight of THF. Such alkylTHF can be represented by the following structural formula. In the formula, any one of R ₁ , R ₂ , R ₃ or R ₄ is 1
an alkyl group containing ~4 carbon atoms;
The remaining three are hydrogen. Examples of such alkyltetrahydrofurans are 2-methyltetrahydrofuran and 3-methyltetrahydrofuran. The catalyst used in the process of the invention is such that the final polymer has the formula or (where 〓〓 represents a polymer chain or a segment thereof, D is hydrogen, an aliphatic or aromatic hydrocarbon group containing 1 to 10 carbon atoms, a halogen atom or a segment of the polymer chain, and and Y is hydrogen, halogen, an aliphatic or aromatic hydrocarbon group containing from 1 to 10 carbon atoms, or fluorine, provided that at least one is fluorine, and R is up to 40 carbon atoms. a straight-chain or branched linking group having atoms in the main chain, and Z is hydrogen, halogen or an aliphatic or aromatic hydrocarbon group containing from 1 to 10 carbon atoms or fluorine) is a homopolymer of ethylenically unsaturated monomer (a) having a group such as that containing a group of It is a copolymer with polymer (b). The linking group defined by R in formula (9) can be a homogeneous group such as an alkylene group,
Or it may be a heterogeneous group such as an alkylene ether group. In preferred catalysts, the linking group contains 1 to 20 carbon atoms in the backbone. In particularly preferred catalysts, R is of the structural formula It is the basis of Examples of monomer (a) include trifluorovinyl sulfonic acid, linear or branched vinyl monomers containing sulfonic acid group precursors, and perfluoroalkyl vinyl ethers containing sulfonic acid group precursors. There are monomers such as Examples of monomer (b) include ethylene, styrene,
Vinyl chloride, vinyl fluoride, vinylidene fluoride, chlorotrifluoroethylene (CTFE), bromotrifluoroethylene (BTFE), vinyl ether, perfluoroalkyl vinyl ether,
Butadiene, tetrafluoroethylene (TFE)
and monomers such as hexafluoropropylene (HFP). Homopolymerization and copolymerization can be carried out by the methods described in US Pat. No. 3,784,399 and the patents cited therein. Monomer ratios are selected to give the resulting polymer a suitable equivalent weight. The catalyst is 950-1500 and preferably 1100-
It has an equivalent weight of 1300. The equivalent weight of the catalyst is the weight in grams of catalyst containing 1 g equivalent weight of sulfonic acid groups, which can be determined by titration. The catalyst has a solubility such that no more than about 5% by weight of the catalyst is dissolved in the reactants at the reaction temperature when the reaction is carried out in batches for the times specified below. preferable. This solubility is determined gravimetrically. It is desirable that the solubility of the catalyst is as low as possible.
This is because it minimizes catalyst losses and allows the process to operate for longer periods without replenishing catalyst. Preferably, this solubility will not exceed about 1% by weight, and even more preferably it will be below the detection limits of current analytical techniques. The catalyst should be effectively free of functional groups other than _-SO3H groups that may inhibit the polymerization reaction. "Effectively removed" means that the catalyst may contain a small number of such groups, but not so much as to adversely affect the reaction or cause contamination of the product. It is. Examples of such functional groups are carboxyl, hydroxyl and amino groups. Catalysts whose polymer chains are derived from perfluorocarbon monomers are preferred for use. Examples of such monomers are tetrafluoroethylene (TFE),
Hexafluoropropylene, CTFE, bromotrifluoroethylene and perfluoroalkyl vinyl ether. Mixtures of monomers can also be used. Even more preferred as the catalyst is a copolymer of TFE or CTFE and a perfluoroalkyl vinyl ether containing a sulfonic acid group precursor (sulfonic acid group forming group). The most preferred of this group are TFE or CTFE and structural formula It is a copolymer with a monomer represented by These polymers are prepared in the sulfonyl fluoride form and then hydrolyzed to the acid form as described in US Pat. No. 3,692,569. The most preferred catalysts are TEF and formulas whose respective monomer weight ratios are 50-75/25-50
It is a copolymer of monomer (10). 1100, 1150 and
Such a copolymer with an equivalent weight of 1500
It is marketed as "Nafion" perfluorosulfonic acid resin by Kompany. The catalyst is usually present in the reactants in a catalytically effective amount. This is usually about 0.01-30% by weight of the reaction mixture, preferably 0.05-15% by weight,
Even more preferably it means a concentration of 0.1 to 10% by weight. The acylium ion precursor used can be any compound capable of producing an acyloxonium ion of formula (1) under the reaction conditions. The term "acyllium ion" used here is

The formula refers to an ion represented by the structure where R is hydrogen or a hydrocarbon group, preferably an alkyl group having 1 to 36 carbon atoms. Representative examples of such precursors are acyl halides and carboxylic acid anhydrides. Anhydrides of carboxylic acids in which the carboxylic acid moiety contains 1 to 36 carbon atoms, especially those containing 1 to 4 carbon atoms, are preferred. Examples of such anhydrides are acetic anhydride, propionic anhydride and formic-acetic anhydride. Because of its efficiency, the preferred anhydride to use is acetic anhydride. Acyllium precursors are usually, at least initially,
It is present in the reaction system at a concentration of 0.1 to 15 mol%, preferably 0.7 to 10 mol%. The molecular weight of the polymeric product can be limited by adding to the reaction system an aliphatic carboxylic acid containing 1 to 36 carbon atoms, preferably 1 to 5 carbon atoms. Acetic acid is preferred because of its low cost and efficiency. Asylium ion precursor/acid weight ratio is 20:1 ~
It should be in the range 0.1:1, preferably 10:1 to 0.5:1. Generally speaking, the more carboxylic acid is used, the lower the molecular weight of the product will be. The aliphatic carboxylic acid is usually added to the reaction at a concentration of 0.1-10%, preferably 0.5-5% by weight of THF. Since the preferred acylium ion precursor, acetic anhydride, reacts with THF and the catalyst to form the corresponding acid, no additional acid addition is necessary. However, the addition of such acids is generally desirable to improve molecular weight control. The acylium ion precursor and the carboxylic acid are reacted at a combined concentration of 0.5 to 20%, preferably 1 to 10% by weight of the reactants, in order to obtain a product with an industrially desirable number average molecular weight of 650 to 30,000. Preferably, it is present in the product. The polymerization reaction can be carried out batchwise or continuously. When carried out in batches, an appropriate amount of
THF, acylium ion precursor, catalyst and carboxylic acid are placed in a reactor and stirred while maintaining optimal reaction conditions. Once the reaction is complete, the catalyst and reactants are separated and the product is then separated from the remainder. If the reaction is carried out continuously, the reaction is preferably carried out in a backmixed slurry reactor using continuous stirring and by continuously adding the reactants and continuously removing the products. It is done. Alternatively, the process can be carried out in a pipeline reactor. In pipeline reactors, this reaction is carried out under plug flow conditions. In this case, the premixed reaction components are passed through a reactor filled with catalyst. The transfer is continuous, the initial feed has little or no mixing with the partially converted reaction components, and the reaction components react while they are transferred. This pipeline reactor is preferably arranged vertically, with the reaction components moving upwardly through the catalyst. This tends to suspend the catalyst and this allows the reaction components to flow more freely.
The reaction components can also be moved downward through the reactor, but this tends to compress the catalyst and restrict the flow of the reaction components. In either a slurry reactor or a pipeline reactor, the temperature of the reaction zone, the concentration of the reaction components in the reaction zone, and the flow rate of the reaction components into or out of the reaction zone vary from about 5 to
Preferably, 85% by weight, preferably 15-60% by weight, even more preferably 15-40% by weight, is adjusted to be converted to ester-terminated PTMEG in each pass through the reactor. The effluent from each pass is recycled to the reactor after product removal. It is also preferred that at least about 40% by weight and even more preferably about 80-90% by weight of the acylium ion precursor be consumed with each pass of the reaction components through the reactor. With proper adjustment of reactant concentrations, flow rates, and temperatures in the feed stream, all of this typically
In a continuous reactor, reaction component residence times of 10 minutes to 2 hours, preferably 15 to 60 minutes and even more preferably 20 to 45 minutes can be achieved. Residence time (min) is determined by measuring the volume of the reaction zone (ml) and then dividing this number by the flow rate of the reaction components through the reactor (ml/min). In a slurry reactor, the reaction zone is the total volume of the reaction mixture. In pipeline reactors, the reaction zone is the catalyst-containing zone. In either batchwise or continuous mode,
Polymerization is usually carried out at atmospheric pressure. However, reduced or elevated pressure can be used to control the temperature of the reactants during the reaction. The temperature of the reactant is 0 to 120°C, preferably 22° to
Maintained within 65℃ range. Preferably, oxygen is removed from the reaction zone.
This can be done, for example, by operating in an inert atmosphere such as dry nitrogen or argon. The reaction time required to reach a given conversion of THF to polymer depends on the conditions under which the operation is being carried out. Therefore, the time will vary depending on temperature, pressure, reactant concentrations, catalyst, and other factors. Generally, however, in continuous operation, the reaction is continued for 10 minutes to 2 hours, preferably 15 minutes to 60 minutes, even more preferably 20 to 45 minutes. In batch mode, the reaction is usually carried out for 1 to 24 hours. Once the polymerization reaction is complete, the catalyst can be separated from the reaction system by filtration, decantation, or centrifugation and reused. If the reaction is carried out in continuous mode, the catalyst can simply be left in the reactor, while fresh reaction components are fed in and the products removed. In either batchwise or continuous mode,
After removal of the catalyst, the polymer product is removed from the reaction system by extracting the remaining unreacted THF, acylium ion precursor, and carboxylic acid by distillation or by stripping with steam or an inert gas (e.g., nitrogen). To separate. Poly(tetramethylene ether) diacetate (PTMEA) thus produced can range in physical properties from clear viscous liquids to waxy solids. The number average molecular weight of this product is approximately
It can be as high as 30,000, but usually from 650 to about 5,000, and more commonly from about 650 to
The range is 2900. Number average molecular weight is determined by end group analysis using spectral analysis methods well known in the art. The molecular weight of PTMEA can be determined within certain limits by varying the ratio of carboxylic acid/acyllium ion precursor in the reactant feed and by varying the total amount of carboxylic acid and precursor in the reactant feed. can be maintained within any desired range by varying the temperature of the catalyst, by controlling the residence time of the reaction components in the reaction zone, and by varying the catalyst concentration. Generally speaking, the use of higher amounts of carboxylic acid and/or acylium ion precursor will give a polymer with lower molecular weight, and lower reaction temperatures are preferred for the production of higher molecular weight polymer;
And higher temperatures favor the formation of lower molecular weight polymers, and higher catalyst concentrations favor the formation of lower molecular weights. The PTMEA thus produced is then converted into PTMEG by reacting it with an alkanol in a basic medium using calcium, strontium, barium or magnesium oxides, hydroxides or alkoxides as catalysts.
Convert it to This conversion is easily accomplished and gives almost catalyst-free PTMEG. This alcoholysis proceeds according to the following formula. where R is an alkyl group containing 1 to 4 carbon atoms and 〓〓 is a poly(tetramethylene ether) polymer chain. In alcoholysis, a mixture of PTMEA, catalyst and alkanol is first produced. This can be done simply by mixing the components together in any order in the reactor. Preferably, the catalyst is first slurried in alkanol and then the slurry is mixed with a solution of PTMEA in alkanol. This mixture contains about 5-80% by weight of
PTMEA is prepared to contain about 0.05-20% by weight catalyst and an amount of alkanol to make up to 10%. Preferably, the mixture contains 20-60% ester, 0.1-5% catalyst and an amount to 100% alkanol. PTMEA can be added to the reactor as needed or it can be supplied directly from the equipment used for its production. The catalyst used in this mixture is calcium,
Barium, strontium or magnesium oxides, hydroxides or alkoxides (the alkyl group containing 1 to 4 carbon atoms). A preferred catalyst is calcium oxide. The catalyst is usually granular and preferably in powder form. The alkanol in the mixture contains 1 to 4 carbon atoms. Methanol is preferred, especially when calcium oxide is used as a catalyst. It is most important that the mixture is basic, ie it has a PH value of 7 or more, preferably about 10-12. The reason is that if the PH value is lower than about 7, this reaction becomes unhelpfully slow or does not proceed at all. In normal cases, this mixture will have inherently adequate values if the component concentrations are kept within the limits recommended herein. If for any reason the component concentrations must be varied from these recommended values, or if acid is introduced into the mixture with one of the components, it may be necessary to change the concentration by adding more catalyst. Therefore, it may be necessary to raise the pH of the mixture to 7 or higher. The mixture is then brought to its boiling point and maintained at that temperature with stirring. During this time, the alkanol/alkyl ester azeotrope vapors formed are continuously removed from the reaction zone. In normal cases,
The boiling point of the mixture ranges from about 50 to 150°C. If higher temperatures are required, the reaction can be operated under pressure up to 100 atmospheres. This boiling and azeotrope removal is continued until the alcoholysis is substantially complete, ie, no more alkyl acetate is formed. Alcoholysis can be carried out in batch or continuous mode. Continuous mode is preferred because of its efficiency. Although the alcoholysis can be carried out in a single stage, it is preferably operated in two stages, especially if carried out continuously.
The reason is that it gives a higher conversion rate. The continuous two-stage process is a precise process, except that the contents of the first reactor are transferred to the second reactor when the alcoholysis is approximately 98% complete (which typically requires a residence time of approximately 90 minutes). It is performed in the same way as the one-stage method. The alcoholysis is completed in the second reactor,
And this usually requires an additional residence time of about 90 minutes. It is desirable to continuously add an amount of alkanol to the second reactor equal to the amount of alkanol in the azeotrope to be removed. After the alcoholysis is complete, the catalyst and other insoluble materials that may be present are removed from the reaction by conventional techniques such as filtration, decantation, or centrifugation. Usually and preferably the catalyst is filtered from the reactants and recycled to one of the reactors. However, the reactants can also be removed from the reactor through a filter, which supports the catalyst and other insolubles and keeps them within the reactor. It may also be desirable to strip residual alkanol and alkyl ester byproducts from the reactants before or after separation of the catalyst. This can be carried out using conventional industrial techniques. PTMEG products can be applied in any conventional use, such as in the production of polyesters or polyurethanes by methods well known in the art. In the examples below a "nafion" perfluorosulfonic acid resin powder with an equivalent weight of 1100 and an average particle size of 0.2-0.5 mm is used and is referred to as the catalyst. All polymerizations were carried out at 22° C. and atmospheric pressure unless otherwise noted. The screen mesh is represented in Tyler-like sizes. Percentages are by weight unless otherwise specified. Although the molecular weight of certain samples has not been determined, the intrinsic viscosity values given instead are indicative of molecular weight variations. Intrinsic viscosity is a value obtained by extrapolating the ratio of the specific viscosity of a given solution to the concentration of that solution to zero concentration. Example 1 A 1.75 g catalyst sample was flame dried and added to a tared flask, which was then added to a 10 ^-5 mm
A vacuum of Hg pressure was applied and heated to 120° C. for 16 hours. By reweighing the flask,
1.60 g of anhydrous catalyst was found to be present. Next, 134.8 g of THF dried over lithium aluminum hydride and 1.08 g of acetic anhydride were distilled into the flask using standard vacuum line techniques and the mixture was stirred for 24 hours. 500 ml (444 g) of THT was then added to reduce the viscosity of the solution and the catalyst was removed by filtration. Evaporate unpolymerized THF under reduced pressure and then heat to 80 °C.
and 89.8g (66% of THF) when dried at 120mmHg.
(wt% conversion) was obtained. This thing is
It has an intrinsic viscosity [η] of 1.05 and an infrared spectral absorption peak at 1750 cm ^-1 characteristic of the acetate end group. Under similar conditions except in the absence of acetic anhydride (and therefore outside the invention), 51.4 g (36
% conversion) is obtained, which has a very high molecular weight [η]=4.04 and shows no presence of acetate end groups. Example 2 Wet catalyst (contains approx. 0.3 g of water, approx. 1.0 g)
Mix with 30ml (26.6g) of THF and the THF
was decanted. Fresh THF (50ml, 44.4g) and 2.16g (2ml) of acetic anhydride were added to the catalyst and the mixture was stirred for 4 hours. The acetic anhydride was in excess sufficient to combine with any water present to form acetic acid. After filtering the catalyst from the reactants, stripping the solvent under vacuum and drying the product at 90 °C and 50 mm Hg, a polymer with a viscosity [η] = 0.30 (30% conversion) was obtained.
12.5g was obtained (Sample 1). Using a dry catalyst and under similar conditions but in the absence of water, [η] = 0.78 into a polymer.
A conversion of 38% THF was obtained in 2 hours (sample 2).
These results are summarized below.

Table Example 3 3 g of catalyst was added to a reaction vessel, various amounts of acetic anhydride and 70 ml (62 g) of a solution of acetic acid in THF were added and the reaction was then stirred at 22° C. for the indicated time. A series of separate batch tests were conducted covering a range of weight ratios of acetic anhydride to acetic acid from 9:1 to 1:9. Samples were removed at time intervals for % conversion and molecular weight measurements. The results are given below (samples 3-9). These experiments show that molecular weight can be a function of the ratio of acetic anhydride to acetic acid and time.

Table: Example 4 As in Example 3, 1 g of catalyst was mixed with 0.36 g of trifluoroacetic acid and 10% acetic anhydride.
Batch polymerization of THF was carried out using 21 ml (18.7 g) of THF solution. The results are given below (samples 10-12).

Table: The resulting polymer was a viscous oil with both acetate and trifluoroacetate end groups. Example 5 A mixture of 75.5 g THF, 3.1 g propionic anhydride and 1.0 g catalyst was stirred for 4 hours. After removing the catalyst by filtration and removing unreacted THF by vacuum distillation, 24.1 g (33.5% conversion) of polymer with propionate end groups were obtained. Example 6 A mixture of 75.5 g THF, 4.2 g formic acid-acetic anhydride and 1.0 g catalyst was stirred for 2.5 hours. After removing the catalyst by filtration and removing unreacted THF by vacuum distillation, 16.3 g (23% conversion) of polymer with [η]=0.33 were obtained. Example 7 THF72.0g, propionic anhydride 5.0g, acetic acid
A mixture of 3.0 g and 1.0 g of catalyst was stirred for 6 hours. Analysis by NMR spectroscopy of the mixture from which the catalyst had been removed by filtration showed that 19% THF was 3:2
was shown to be converted into a polymer having propionate and acetate end groups and having M1500 in a ratio of . Example 8 Contains 2g catalyst, 100g THF, M650
25 g of a mixture of 10 g of PTMEG and 6 g of acetic anhydride
Stirred at ℃ for 4 hours. The catalyst was then separated from the mixture by filtration and unreacted monomers were removed by vacuum distillation. The polymer yield was 42 g and the molecular weight of the PTMEG diacetate was 2000. Example 9 Catalyst sample 1 dried as in Example 1
g was added to a monomer mixture consisting of 80 g THF and 20 g 3-methyl-tetrahydrofuran (3MeTHF). A mixture of 9g acetic anhydride and 1g acetic acid was added and the system was stirred at 22°C for 4 hours. At this point, the polymerization was stopped by removing the catalyst from the colorless viscous polymer solution. Unreacted monomer was removed from the reaction by vacuum distillation and the polymer product was extracted with water and dried at 2 mm pressure and 80° C. to constant weight. Conversion to diacetate copolymer 56% Yield of pure copolymer (% of total polymer) 94% M 3130 Molecular composition of copolymer 11% 3MeTHF units 89% THF units Example 10 As in Example 1 1 g of dried catalyst sample was added to 40
of THF and 10 g of 2-methyltetrahydrofuran (2MeTHF). A mixture of 4.5 g acetic anhydride and 0.5 g acetic acid was added and the system was stirred for 5 hours. At this point, the polymerization was stopped by removing the catalyst from the colorless viscous polymer solution. Unreacted monomer was removed from the reaction by vacuum distillation and the polymer product was washed with water and dried as in Example 9. Conversion to diacetate copolymer 44% Yield of pure copolymer (% of total polymer) 89% M 1800 Molecular composition of copolymer 6.5% 2MeTHF units 93.2% THF units Example 11 Volume of 50 ml and 25 mm A vertical pipeline reactor was used that had an internal diameter and stainless steel screen packs (120 mesh) to retain the catalyst at each end of the tube. A valve and tube system was provided to supply the reactants below the bottom screen pack and remove the reactants and products from above the top screen pack. A constant temperature bath surrounded the reactor. Catalyst 5 dried as in Example 1 in the reaction chamber
g, and a reactant feed composition of 90% THF, 9% acetic anhydride, and 1% acetic acid was used to feed the reactants and remove the product at a rate to provide a controlled residence time. . PTMEA when using a residence time of 190 minutes
The conversion of THF to is 49% and M is 1500
It was ~2000. At a contact time of 425 minutes, the conversion was 74% and the polymer had an M900~
Had 1200. Experiments conducted in the same reactor using the same feed composition and residence time of 43 minutes resulted in 39% THF conversion and 5g PTMEA/
A productivity of g catalyst/hour was obtained. This same system can be used to operate in either upward or downward flow. Example 12 A backmixed slurry reactor with a volume of 100ml was used. The reactor was operated with a liquid volume of 50 ml. The reaction mixture was stirred magnetically. A constant temperature bath surrounded the reactor. An initial charge of 1 g of catalyst dried as in Example 1 and 3.5% acetic anhydride and 1.5%
The reactor was operated at 42° C. with a residence time of 52 minutes using a reactant feed composition containing % acetic acid in THF. After steady-state operation is obtained, the polymer
It was produced at 21% conversion and was found to have an M2000-2200. The productivity of this system is
It was found to be 11.1 g PTMEA/g catalyst/hour. Similar experiments conducted under identical operating conditions but in a pipeline reactor showed that 9 g
PTMEA/g catalyst/hour was given. This PTMEA had M=4800. Example 13 PTMEG was produced from PTMEA in a two-step reaction. Both reactors were of 500 ml capacity and arranged so that the flow of the effluent was by gravity. A 40 wt% PTMEA solution in methanol and a 5 wt% calcium oxide slurry in methanol were prepared separately. 4-5ml of PTMEA solution/
was fed to the first reactor at a rate of 1.5 min. The CaO slurry was fed to the first reactor at a rate to provide a reaction mixture containing 0.5% CaO by weight of PTMEA. From there the reaction mixture flowed into the second reactor. The temperature of the reactants in each reactor was maintained at about 68°C and the PH of the reactants was about 11.5. The methanol/methyl acetate azeotrope vapor produced in each reactor was continuously removed. Residence time in each reactor was approximately 90 minutes. The reactants from the second reactor flow into a filter to remove calcium oxide and other insoluble materials, and from there into a rotary evaporator to remove remaining methanol and methyl acetate and produce The material was dried to constant weight. After 8 hours of continuous operation, 430 g of PTMEG was recovered. Infrared analysis of the product showed the absence of carbonyl absorption at 1750 cm ^-1 . this is
It implies a complete conversion of PTMEA to PTMEG. Example 14 25g of PTMEA sample was dissolved in 100ml of methanol. After addition of 0.5 g of calcium hydroxide, the mixture was heated to 65° C. and kept at that temperature with stirring for 3 hours. Methanol formed during this time/
The methyl acetate azeotrope vapor was removed. The product was then dried at 85° C. for 1 hour under a vacuum of about 1 mm Hg. 0.1 g superaid was added and the product was filtered to remove insoluble material. The final product contained less than 2 ppm calcium as determined by flame photometry. Infrared spectrum analysis showed that the alcoholysis was complete. Example 15 Place 25g of PTMEA sample as in Example 14.
Dissolved in 100ml methanol. 0.5 g of calcium oxide was added in place of the calcium hydroxide and the mixture was treated as in Example 14. Infrared spectrum analysis showed that the alcoholysis was complete. Example 16 36 g of PTMEA sample was dissolved in 160 ml of methanol and 1 g of barium oxide was added to this solution. The resulting slurry was heated to 65°C and held there for 3 hours while the methanol/methyl acetate azeotrope vapors formed were continuously removed. The resulting product was treated as in Example 14 to produce PTMEG without ester groups.

Claims (1)

[Scope of Claims] 1. In producing ester-terminated poly(tetramethylene ether) glycol by polymerizing tetrahydrofuran alone or with alkyl-substituted tetrahydrofuran and tetrahydrofuran, the polymerization is performed using (A) an acyl halide or carboxylic acid anhydride; an acyllium ion precursor selected from the group consisting of (B) formula [formula] or [formula] where 〓〓 represents a polymer chain or a segment thereof, D is hydrogen, 1 to 10 carbon atoms an aliphatic or aromatic hydrocarbon group, a halogen atom or a segment of the polymer chain containing
X and Y are hydrogen, halogen, aliphatic or aromatic hydrocarbon groups containing from 1 to 10 carbon atoms, or fluorine, provided that at least one is fluorine, and R contains up to 40 carbon atoms. a straight-chain or branched linking group having in the main chain, and Z is hydrogen, halogen, an aliphatic or aromatic hydrocarbon group containing 1 to 10 carbon atoms, or fluorine) and optionally (C) an aliphatic carbon containing from 1 to 36 carbon atoms. A process for the polymerization of tetrahydrofuran or alkyl-substituted tetrahydrofuran, characterized in that it is carried out in an acid-containing reaction medium. 2 The acylium ion precursor is acetic anhydride, and the catalyst is tetrafluoroethylene or chlorotrifluoroethylene, and the formula A hydrolyzed copolymer with a monomer represented by ), the method according to item 1 above.