JPH0446291B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides a method for producing low or medium molecular weight polyoxytetramethylene glycol (hereinafter abbreviated as PTMG) by dehydration condensation of 1,4-butanediol, and a method for producing polyoxytetramethylene glycol (hereinafter abbreviated as PTMG) between 1,4-butanediol and tetrahydrofuran (hereinafter THF). ) or 1,
The present invention relates to a method for producing low or medium molecular weight PTMG by dehydration condensation or polymerization of 4-butanediol, THF and PTMG oligomer. PTMG is an industrially useful polymer that is used as the main raw material for urethane used in spandex and synthetic leather, as well as in surfactants, solvents, pressure fluids, etc. The applications to which PTMG is suited differ depending on its molecular weight, and PTMG having various molecular weights are used. A conventionally known method for synthesizing PTMG is to polymerize THF, then add water to hydrolyze it and convert the terminal into an OH group. In that case, the polymerization catalyst may be a super strong acid such as fluorosulfonic acid or fuming sulfuric acid, perchloric acid-acetic anhydride, naphion resin (fluorinated sulfonic acid resin)-acetic anhydride, BF ₃ -HF-
A system in which an acid anhydride is combined with a protic acid such as acetic anhydride or a Lewis acid is used. In these conventionally known methods, the terminal end of the polymer immediately after THF polymerization is not a hydroxyl group, but is terminated, for example, as a -SO ₃ H group or -OCOCH ₃ group, and water or alkaline water is added to this to hydrolyze it. It is necessary to prepare PTMG with hydroxyl groups at both ends, which causes many industrial disadvantages. For example, hydrolysis of terminal acetyl groups obtained in the presence of acetic anhydride requires harsh conditions of refluxing for 1 to 5 hours to avoid even traces of acetyl groups remaining, and also requires an alkali. This makes it difficult to recycle the acid catalyst. When using a fluorosulfonic acid catalyst, hydrolysis of the generated SO ₃ H group proceeds easily by simply adding water, but the fluorosulfonic acid is decomposed into hydrogen fluoride and sulfuric acid, requiring the use of expensive reagents. In addition to consuming a large amount, a large amount of equipment had to be invested in processing the generated HF. Under such circumstances, the inventor has developed a new
As a method for synthesizing PTMG, both ends are simultaneously dehydrated and condensed with 1,4-butanediol.
We investigated a method to synthesize PTMG, which has an OH group. As a result, it was discovered that the objective could be achieved by carrying out the reaction in the presence of a heteropolyacid, and the present invention was completed based on this knowledge. That is, in the present invention, in the presence of a heteropolyacid in which 15 molecules or less of water are coordinated or present per molecule,
dehydrating and condensing 1,4-butanediol;
Alternatively, by dehydration condensation or polymerization of 1,4-butanediol and THF, or 1,4-butanediol, THF, and PTMG oligomer.
This is a method for manufacturing PTMG. Normally, heteropolyacids are synthesized as 20-40 hydrates, but even if they are brought into contact with 1,4-butanediol or a mixture of 1,4-butanediol and THF in this state, they exhibit no polymerization activity. It was not recognized. However, when we examined the polymerization activity after drying the above heteropolyacid and changing its hydration number, we surprisingly found that when the hydration number of the heteropolyacid molecule was lowered to 15 or less, polymerization activity appeared. , 1,4-
PTMG was directly synthesized by dehydration condensation of butanediol. In particular, PTMG was synthesized in higher yields when the hydration number was 8 or less. At this time, when THF was allowed to coexist, both 1,4-butanediol and THF were consumed, and in this case as well, PTMG with OH groups at both ends was synthesized. As water is produced as the dehydration condensation reaction of 1,4-butanediol progresses, the polymerization activity disappears when the amount of water in the system exceeds 15 times the mole of heteropolyacid. Therefore, in order to continue the reaction, it is necessary to remove water from the system by distillation or other methods to maintain the hydration number of the heteropolyacid at 15 or less. 1,4-butanediol and THF, or 1,
When PTMG is synthesized from 4-butanediol, THF, and PTMG oligomer, it is necessary to similarly maintain the hydration number of the heteropolyacid at 15 or less. However, in this case, if the molecular weight of the polymer produced is well balanced between the amount of water consumed as the terminal of PTMG and the amount of water produced by dehydration of 1,4-butanediol or PTMG oligomer, , it is possible to continue the reaction without removing water from the system. vice versa,
If there is insufficient water for the PTMG end, add water.
It is possible to add up to 15 times the molar amount of heteropolyacid, and due to the presence of water, it can be added directly to both terminals.
It is possible to synthesize PTMG with OH groups. When the number of coordinated waters in a heteropolyacid exceeds 15, it no longer exhibits polymerization activity as described above, but the value of the number of coordinated waters that is actively suitable for polymerization varies depending on the type of heteropolyacid. In addition, since the molecular weight of synthesized PTMG changes depending on the number of coordinated waters, when synthesizing PTMG with almost uniform molecular weight, it is necessary to select a suitable coordinated water determined by the type of heteropolyacid and the desired molecular weight. It is necessary to control the number of reactions. Although the mechanism of this reaction is not clear, it is thought that the OH group of butanediol dissociates on the catalyst, and polymerization proceeds from this. The heteropolyacid used in the present invention forms a solid phase in 1,4-butanediol when the number of coordinated waters is small, and dissolves in 1,4-butanediol to form a homogeneous phase when the number of coordinated waters increases. becomes. Furthermore, in systems to which THF is added, even if there is a large amount of coordinated water, it may not dissolve uniformly and may exist as a lower layer of the two liquid phases, although this varies depending on the amount of THF. The heteropolyacids in the present invention include Mo, W, V
A general term for oxyacids produced by the condensation of at least one oxide of the above with other elements such as P, Si, As, Ge, B, Ti, Ce, Co, etc. The atomic ratio is 2.5-12. Specific examples of these heteropolyacids include phosphomolybdic acid, phosphotungstic acid, phosphomolybdotungstic acid, phosphomolybdovanadate, phosphomolybdotungstovanadate, phosphotungstovanadate, phosphomolybdoniobic acid, and tungstic silicoic acid. , silicomolybdic acid, silicomolybdotungstic acid, silicomolybdotungstovanadate, germanium tungstic acid, borotungstic acid, boromolybdic acid, boromolybdotaungstic acid, boromolybdovanadate, borosilicate tungstovanadate, Cobalt molybdic acid, cobalt molybdic acid, cobalt tungstic acid, arsenic molybdic acid, arsenic tungstic acid,
These include titanium molybdate and cerium molybdate. The amount of heteropolyacid used is not particularly limited, but if the amount of heteropolyacid in the reactor is small,
The polymerization rate is low, and 0.1 to 20 times the weight of the raw material is used. In order to carry out the reaction without removing the water generated by dehydration condensation of 1,4-butanediol or PTMG oligomers from the system, the number of coordinated waters of the heteropolyacid should not exceed 15 due to the generated water. It is necessary to adjust the amount of Otherwise, when the number of coordinated waters of the heteropolyacid exceeds 15, the polymerization activity disappears and the PTMG yield becomes low. When the reaction temperature is raised, the degree of polymerization tends to decrease, and a temperature of 0 to 150°C, particularly 30 to 80°C, is preferable. 150
When the temperature exceeds ℃, the yield decreases drastically. Below 0°C, the reactivity is extremely low and has no practical value. The time required for the reaction varies depending on the amount of catalyst and reaction temperature, but is 0.5 to 50 hours. The reaction is carried out between 1,4-butanediol and a heteropolyacid with a predetermined hydration number, or between 1,4-butanediol and THF, or between 1,4-butanediol and
Since the reaction can be carried out while stirring the THF and PTMG oligomers and a heteropolyacid having a predetermined hydration number, no particular solvent is required, but an inert substance may be added to the reaction. The reaction format is not particularly limited and may be a commonly used reactor with a stirring function. Moreover, either batch type or continuous type can be implemented. After the polymerization reaction, PTMG is removed by filtration if the catalyst is in a solid phase, by phase separation if the catalyst is a liquid and separated into two phases, or by extraction etc. if the catalyst is uniformly dissolved.
and the catalyst are separated and recovered. The recovered catalyst can be used repeatedly by adjusting the hydration number. The present invention will be explained below with reference to Examples. Example 1 36.6 g of 1,4-butanediol is charged into a container equipped with a stirring device. Next, 91.2 g of phosphotungstic acid (H ₃ PW ₁₂ O ₄₀ ) heated at 250°C for 3 hours to make it anhydrous was added (1,4
- The number of moles of butanediol is approximately 13 times the number of moles of phosphotungstic acid, and the number of coordinated waters of the heteropolyacid does not exceed 15 even after the dehydration condensation reaction).
Seal the container, set the temperature to 25°C, and stir for 30 hours. Phosphortungstic acid initially exists as a solid phase, but as the dehydration condensation reaction progresses, it uniformly dissolves. After reaction, add 200 g of water and 200 g of chloroform to the system.
g and shake, then allow to separate into two phases.
The catalyst is recovered from the aqueous phase. 1.0 g of polymer was obtained by removing unreacted 1,4-butanediol and chloroform from the chloroform phase by distillation. As a result of infrared spectrum and NMR spectrum measurements, the polymer has OH groups at both ends, and is PTMG.
It was decided that Obtained as a result of gel permeation chromatography (GPC) measurement
PTMG had a number average molecular weight of 400 with a molecular weight distribution ranging from several hundred to several thousand. Comparative Example 1 The same operation as in Example 1 was carried out except for using phosphotungstic acid having a coordination water number of 16, but no polymer was obtained from the chloroform phase. Example 2 In a container equipped with a stirrer and a reflux condenser, 1,4
-Prepare 35g of butanediol. Next, 90 g of various heteropolyacids shown in Table 1 in an anhydrous state are added. After setting the temperature at 60° C. and continuing stirring for 15 hours, 200 g of water and 200 g of chloroform are added to the system, stirred, and then separated into two phases. PTMG was obtained by removing unreacted 1,4-butanediol and chloroform from the chloroform phase by distillation.
Table 1 shows the number average molecular weight and yield of the obtained PTMG.
Shown below.

【table】

[Table] Examples 3 to 5 and Comparative Example 1 200 g of anhydrous THF (water content 30 ppm or less) was added to a container equipped with a stirring device and a reflux condenser, and then 100 g of anhydrous phosphotungstic acid was added.
Add. Next, 1,4-butanediol was added to Table 2.
Add the amount described in , set the temperature to 60°C, and stir for 4 hours. After the reaction, the mixture is allowed to stand at room temperature to separate into two liquid phases, and the lower catalyst phase is separated. A polymer is obtained by removing unreacted THF from the upper phase. Note that unreacted 1,4-butanediol was not detected in any case except for the comparative example, indicating that 100% reaction had occurred. As a result of infrared spectrum and NMR spectrum measurements, it was determined that the polymer had OH groups at both ends and was PTMG. Table 2 shows the polymerization results and the number average molecular weight determined by GPC.

[Table] Example 6 Polymerization was carried out using the continuous polymerization apparatus shown in FIG. First, 200 g of phosphotungstic acid (H ₃ PW ₁₂ O ₄₀ 3.5 H ₂ O) having a coordinated water number of 3.5 was charged into a polymerization tank 1 having a volume of 300 ml and equipped with a stirring device and a reflux condenser. Contains 1.8% by weight of butanediol
Add 150g of THF and stir. Polymerization tank temperature 60℃
After stirring for 4 hours at a setting of 32 ml/hr, a field of THF containing 1.8% by weight of 1,4-butanediol is started. The reaction is carried out by circulating the liquid from the lower layer between the polymerization tank liquid and the phase separation tank 2, and removing the phase-separated upper layer by overflow.
Unreacted THF is removed from the overflowing upper phase liquid by distillation to obtain PTMG. In addition, unreacted 1,
4-Butanediol is hardly detected.
Continuously operated for 100 hours, with a number average molecular weight of 1600
Obtained 850g of PTMG. Comparative Example 2 In a container equipped with a stirring device and a reflux condenser, the water content was
Add 200g of THF with a concentration of 30ppm or less, and then add 100g of phosphotungstic acid with a coordination water number of 16. Next, 6.7 g of 1,4-butanediol was added, the temperature was set at 60°C, and stirring was performed for 4 hours. After the reaction, the mixture is allowed to stand at room temperature to separate into two liquid phases, and the lower catalyst phase is separated. 1,4-butanediol that remained unreacted with THF was recovered from the upper phase, and PTMG was not obtained. Example 7 In a container equipped with a stirring device, add water with a water content of 30 ppm or less.
THF100g and 1,4-butanediol 3g and 2~
Add 6 g of PTMG oligomer around tetramer.
Next, 50g of anhydrous silicotungstic acid
Add. Seal the container and set the temperature to 30℃ for 15 minutes.
Stir for hours. After the reaction, the mixture is allowed to stand at room temperature to separate into two liquid phases, and the lower catalyst phase is separated. Unreacted THF is removed from the upper phase by distillation, and the number average molecular weight is determined.
Obtained 2000 PTMG40g.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a continuous polymerization apparatus in Example 6. In the figure, 1 is a polymerization tank, 2 is a phase separation tank, and 3
indicates a distillation column.

Claims (1)

[Claims] 1. 1,4-butanediol, 1,4-butanediol and tetrahydrofuran, or 1,4-butanediol and 1,4-butanediol in the presence of a heteropolyacid in which not more than 15 molecules of water are coordinated or present per molecule. A method for producing polyoxytetramethylene glycol, which comprises dehydrating and condensing oligomers of tetrahydrofuran and polyoxytetramethylene glycol.