JP2003002964A - Method for alkoxylating polyetherpolyols - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for alkoxylating a polyetherpolyol, by which the hydroxyl group of the polyetherpolyol can efficiently be alkoxylated without a complicated operation. SOLUTION: This method for alkoxylating the terminal hydroxyl group of the polyetherpolyol, comprising reacting the polyetherpolyol with an alkali metal alkoxide, uses a reactor which has a vacuum evaporator and a stirrer comprising a stirring shaft installed from the outside of the reactor and a flat blade attached to the stirring shaft.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for alkoxidizing a terminal hydroxyl group of a polyether polyol.

[0002]

2. Description of the Related Art Hitherto, as a method for alkoxide-forming a polyether polyol, a method for alkoxide-forming by a dealcohol reaction between a polyether polyol and an alkali metal alkoxide has been performed. However, when the polyether polyol has a large molecular weight and a high viscosity, there is a problem that as the alkoxide conversion rate of the terminal hydroxyl group increases, the intermolecular force increases and the viscosity rapidly increases and the reaction rate decreases. It is considered that the polyether polyol has a hydroxyl group at the terminal, and therefore hydrogen bonds work between the molecules, but the terminal hydroxyl group is alkoxidized, that is, -OH becomes -O ^- Na ^+. As a result, the intermolecular force is considered to shift from a hydrogen-bonding one to an ionic-bonding one, so that in polyether polyols, viscosity increases due to the alkoxide of the terminal hydroxyl group, and the dealcoholization rate decreases and the reaction rate decreases. Is believed to decline.

In order to solve this problem, Japanese Patent Laid-Open No. 7-9
No. 7440 discloses a method of increasing the dealcoholization rate by passing an inert gas into the reaction system. In JP-A-10-087814, this reaction is carried out in the presence of a non-reactive solvent to evaporate the non-reactive solvent together with the alcohol, and then the evaporated non-reactive solvent is separated from the alcohol and returned to the system. It discloses a method of suppressing an increase in viscosity by allowing a non-reactive solvent to exist in the reaction system. Further, in JP-A-10-120779, in order to prevent an increase in viscosity, a series of operations for reacting a halogenated olefin after alkoxidation in a method of introducing an unsaturated group with a halogenated olefin after an alkoxide reaction is prevented. A method of proceeding the reaction is disclosed.

[0004]

When these conventional techniques are used, as the reaction proceeds, the electrical properties of the terminal groups change, and the intermolecular force changes. It is possible to solve the problem that the polymer becomes highly viscous due to the two phenomena that the amount of the monomer or the polymer diluting solvent) decreases, the mixing time / dealcoholization rate decreases, and the reaction becomes slow. However, when inserting an active gas or circulating a non-reactive solvent,
Complex equipment is required. In addition, when conducting an experiment a plurality of times, it can be applied when introducing an unsaturated group, but cannot be used when applying an alkoxidized end group to another reaction. A reaction time is also required to carry out. There has been a demand for a method for alkoxide conversion of polyether polyols which can solve these problems by using a simple apparatus.

[0005]

In view of the above situation, the inventors of the present invention have conducted extensive studies, and as a result, by reacting a polyether polyol with an alkali metal alkoxide, the end of the polyether polyol is In the method for alkoxide formation, a reaction tank having a vacuum devolatilization facility, a stirring shaft rotatable from outside the tank, and a flat blade on the shaft is used, is used. An alkoxide conversion method has been found.

That is, the present invention is a method for reacting a polyether polyol with an alkali metal alkoxide to alkoxide the hydroxyl group end of the polyether polyol, which has a vacuum devolatilization facility and a stirring shaft from outside the tank. A reaction vessel having a stirring blade installed on the shaft and having a flat blade with a blade height of 0.25 or more with respect to the liquid depth and a blade diameter of 0.35 or more with respect to the tank diameter is provided at the bottom of the reaction tank. It relates to a method for alkoxidizing polyether polyols, characterized by being used.

In a preferred embodiment, the stirring blade has one or a plurality of blades or stirring blades, and the total height of the stirring blades is 0.8 or more with respect to the liquid level. Regarding the described method.

In a further preferred embodiment, the stirring blade has flat plate blades arranged at the bottom of the reaction tank at the lowermost stage, and further comb-shaped blades are attached at the middle and upper stages, and the stirring blade is positioned at the lowermost stage. To the flat blade, which is adjacent to the lower flat blade, and the upper middle blade that is adjacent to the lower flat blade. The comb-shaped blade has an overlap in the axial direction, and the comb-shaped blade located in the middle stage is rotated at an intersection angle of less than 90 degrees with respect to the comb-shaped blade in the upper stage adjacent thereto. A method according to any one of the preceding claims, wherein the middle comb-shaped blade and the upper comb-shaped upper blade adjacent to each other arranged in front of the direction have an overlap in the axial direction. .

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION As a reaction tank used in the present invention,
It has a vacuum evacuation facility and a stirring shaft that can be rotated from the outside of the reaction vessel is installed in the reaction vessel. The shaft has a height of 0.25 or more with respect to the liquid depth at the bottom of the reaction vessel, and with respect to the vessel diameter. It is possible to use a reaction tank having a flat blade of 0.35 or more.

As a vacuum exhaust facility, a reciprocating vacuum pump
Oil rotary vacuum pumps, mechanical boosters, diffusion pumps, and various ejectors may be used, but are not limited to these. Moreover, you may install a condenser mist trap filter suitably in a vacuum piping.

The shape of the reaction tank is cylindrical, conical,
Examples thereof include an elliptical shape, but a cylindrical shape is preferable because good mixing and flow can be obtained. The bottom of the reaction tank is preferably a semi-ellipsoidal mirror plate in terms of liquid circulation and flow.

The rotary stirring shaft may be installed at any position in the reaction tank, but is preferably installed at the center of the reaction tank for the reason of obtaining good mixing and flow.

As the flat blade, a conventionally known flat blade can be used without limitation, and the stirring blade may have a wavy structure.

The stirring blade according to the present invention is a type of stirring blade which is considered to have a streamline in the reaction tank which is close to one stroke, has no stagnant portion in the entire reaction tank, and is unlikely to form a plurality of vortices. And, for example, Proceeding of
3rd. International Symposi
um on Mixing in Industry
l Processes, September 19-2
2, 1999, Osaka, Japan, pp. 85-
90, Asano, K; "The Ev.
allocation of Large-Scale Im
Large-Sca in Pellers ”
It is a le Impeller (large wing).

The flat plate blade is installed at the bottom of the reaction tank, the lower part is close to the bottom of the tank, and the height is 0.25 with respect to the liquid depth.
Or more, preferably 0.3 or more, and the blade diameter is 0.
It is not less than 35, preferably not less than 0.45, and the upper limit is such a size that it does not come into contact with the reaction tank, baffles and other equipment. If the height is less than 0.25 with respect to the liquid depth, the discharge flow rate from the flat blade installed in the lower part will not be sufficient, and the same will be true when the blade diameter is less than 0.35 with respect to the tank diameter. Since the discharge flow rate is not sufficient, the flow discharged from the lower flat blade does not reach the upper layer of the liquid, and the flow line does not become close to one stroke in the reaction tank, so the flow stagnation point and local vortex Is generated, and the mixing performance in the tank is deteriorated, which is disadvantageous.

Further, the stirring blade is composed of one or a plurality of stirring blades or stirring blades, and the total height of the stirring blades is 0.8 or more, preferably 0.9 or more, more preferably the liquid depth. Is 1.0 or more, and the upper limit cannot be limited considering the case of taking it out of the liquid surface. In particular, the total height of the stirring blades becomes 1.0 or more, and the stirring blades stick out from the liquid surface, which is advantageous in that the gas-liquid interface is disturbed and the alcohol removal rate is accelerated. If the total height of the stirring blades is less than 0.8 with respect to the liquid depth, and if a space without stirring blades is created near the liquid surface, the circulating flow near the liquid surface will slow down and accumulate. A portion is likely to be generated, and it is inefficient in removing alcohol by-produced in the reaction, which is inconvenient to apply to this reaction. When the total height of the stirring blades is less than 0.8 with respect to the liquid depth and there are multiple stirring blades, the space between the stirring blades in the axial direction becomes large and the streamline of the reaction tank is one stroke. The state is not as written, and a plurality of vortices are present, which deteriorates the mixing performance in the tank, which is inconvenient for application to this reaction.

It is preferable to install the baffle because it has an effect of converting the swirling flow discharged from the lower flat plate blade into an ascending flow. The shape of the baffle is not particularly limited as long as it does not contact the blade, but for example, a flat plate type or Japanese Patent Laid-Open No. 09-0
It may be an inclined type as shown by 52037, or a plurality of sheets may be installed. As the flat plate blade, for example, a flat plate-shaped bottom paddle described in JP-A-9-108557 is attached to the bottom portion, and a lattice blade composed of a vertical member and a horizontal member is attached to the upper portion thereof, JP-A-5-49890. The paddle blades located in the upper stage described in Japanese Patent Publication No. JP-A-5-247199 are arranged in such a manner that they are arranged in the direction of rotation at an intersecting angle of 45 to 75 degrees with respect to the lower paddle blades vertically adjacent to each other. Blend blade, a stirring shaft provided in the central portion of the reaction tank described in JP-A-10-24230, a flat plate blade arranged at the bottom of the reaction tank in the lowermost stage, and comb-shaped blades in the middle and upper stages. With the flat blade located at the lowermost stage, the adjacent comb blades at the middle stage are arranged in front of the flat blade at a crossing angle of less than 90 degrees in the direction of rotation, and The flat blade and the upper middle The comb-shaped blade has an overlap in the axial direction, and the comb-shaped blade located in the middle stage is rotated with respect to the comb-shaped blade in the upper stage adjacent to the comb-shaped blade at an intersection angle of less than 90 degrees. And the upper comb-shaped blade adjacent to the upper comb-shaped blade arranged in front of each other have an overlap in the axial direction (hereinafter,
As this stirring blade, a stirring blade described in JP-A-10-24230) or the like can be preferably used. Specifically, for example, Soken Chemical Co., Ltd. product name: Hi-F mixer, Shinko Pantech Co., Ltd. product name: Full Zone,
Sumitomo Heavy Industries, Ltd. product name: Maxblend etc. can be mentioned. In the present invention, of these,
The stirring shaft equipped with the stirring blade described in JP-A-10-24230 is preferable even if it is a highly viscous liquid because of good mixing characteristics.

When the stirring blades described above are used in the terminal alkoxide reaction of polyether polyols,
Even if the viscosity changes, the flow in the tank circulates largely, and the stagnant portion of the liquid in the tank becomes extremely small. These effects prevent the dealcoholization rate from decreasing with the increase in viscosity, disperse the solidified metal alkoxide uniformly throughout the tank, improve the heat transfer performance in the reaction tank, and reduce the terminal alkoxide reaction rate. Is preventing.

By applying the stirring blades exemplified above, the problems of the present invention can be solved as described below.

The molecular weight of the polyether polyols used in the present invention is not particularly limited, but the number average molecular weight in terms of polystyrene in gel permeation chromatography (GPC) is 1,000 to 100,000.
It is preferably 0.

The main chain structure of the polyether polyol may be a polymer having a structure represented by --RO-- as a repeating unit, wherein R is selected from the group consisting of hydrogen, oxygen and nitrogen. It may be a divalent organic group having 1 to 20 carbon atoms and containing at least one selected as a constituent atom. Further, it may be a homopolymer in which all the repeating units are the same, or a copolymer containing two or more kinds of repeating units. Further, the main chain may have a branched structure.

The main chain structure of polyether polyols is
For example, it can be obtained by ring-opening polymerization of a monoepoxide in the presence of an initiator and a catalyst.

Specific examples of the initiator include ethylene glycol, propylene glycol, butanediol, hexamethylene glycol, methallyl alcohol, bisphenol A, hydrogenated bisphenol A, neopentyl glycol, polybutadiene diol, diethylene glycol, triethylene glycol, polyethylene. Dihydric alcohols such as glycol and polypropylene glycol, polypropylene triol, polypropylene tetraol, dipropylene glycol, glycerin, trimethylol methane, trimethylol propane, pentaerythritol and other polyhydric alcohols and various oligomers having multiple hydroxyl groups. To be

Specific examples of the monoepoxide include ethylene oxide, propylene oxide, α-butylene oxide, β-butylene oxide, hexene oxide, cyclohexene oxide, styrene oxide,
Examples thereof include alkylene oxides such as α-methylstyrene oxide, alkyl glycidyl ethers such as methyl glycidyl ether, ethyl glycidyl ether, isopropyl glycidyl ether, and butyl glycidyl ether, allyl glycidyl ethers, and aryl glycidyl ethers.

As the catalyst, there are already known alkali catalysts such as KOH and NaOH, acidic catalysts such as trifluoroborane-etherate, and complex metal cyanide complex catalysts such as aluminoporphyrin metal complex and cobalt zinc cyanide-glyme complex catalyst. Things are used. In particular, it is preferable to use a double metal cyanide complex catalyst with less side reactions, but other catalysts may be used.

The alkali metal in the alkali metal alkoxide used in the present invention is particularly preferably sodium or potassium. The alcohol component constituting the alkali metal alkoxide is preferably an alcohol having a carbon number of 6 or less from the viewpoint of easiness of evaporation, methanol, ethanol, n-propanol and isopropanol are particularly preferable, and methanol and ethanol are most preferable. As the alkali metal alkoxide, a powder alone or a diluted alcohol solution is used. Those diluted with an alcohol solution are easily dispersed in the polymer, and those diluted as an alcohol solution are preferable.

The amount of the alkali metal alkoxide added depends on the target alkoxide conversion rate of the polyether polyols and the viscosity of the polyether polyols. For example, polyether polyols (initial viscosity of 130 Pa at 0.3 Pa · s In the case of introducing an unsaturated group into 90 mol% or more of the hydroxyl group of 1), the alkali metal alkoxide is preferably 1.0 to 1.8 times equivalent to the hydroxyl group of the polyether polyol. If the amount of alkali metal alkoxide is too small, it will take a long time until the alkoxide conversion rate reaches the target, and if it is too large, it is economically unfavorable. Further, the polyether polyols are dehydrated before carrying out this reaction, but if they contain water, it is necessary to add an extra alkali metal alkoxide by the amount of the water.

The terminal alkoxide reaction of polyether polyols is an equilibrium reaction as shown by R ¹ --OH + R ² --OM ← → R ¹ --OM + R ² --OH (Equation 1). Here, R ¹ —OH represents a terminal hydroxyl group of polyether polyols, and R ² —O
M represents a metal alkoxide of the alkali metal M.
In this reaction, the alcohol represented by R ² —OH is discharged to the outside of the reaction system to promote the alkoxide formation at the terminal. In the actual operation, evacuation is performed with a vacuum evacuation facility, and the alcohol is distilled off while the alkoxide formation reaction at the terminal proceeds. The temperature of the alkoxide reaction is suitably 25 to 150 ° C. If the temperature is too low, it becomes inefficient in distilling off the alcohol produced as a by-product, and if the temperature is too high, the polymer or alkali metal alkoxide may decompose.

The thus obtained terminal alkoxidized polyethers can be used for modifying the terminal group by reacting with various electrophiles and halogen compounds. Further, it can be used for polymerizing polyethers by reacting with a polyvalent halogen compound.

[0030]

EXAMPLES In the following experiments, the power of both Examples and Comparative Examples was an initial power of 3 kW / m ³ , and the evacuation rate for distilling methanol was constant with respect to the polymer weight.
The experiment was carried out at 0 m ³ / min · t-polymer. Example 1 As shown in FIGS. 1 and 2, stirring was performed with h = 0.36H, the blade diameter was 0.7 with respect to the tank diameter, and the total height of the stirring blades was 1.47 with respect to the liquid surface. Baffle width 0.0 for blade and tank diameter D
A polyoxypropylene polyol with sufficient water removed was charged into a reaction tank equipped with four baffles having a size of 8D and a gap of 0.02D.
Viscosity at 0 ℃ is 0.32P as measured by B-type viscometer
When introducing an unsaturated group to the terminal of a.s), 1.2 times equivalent of sodium methoxide (28% methanol solution) is added to the total amount of hydroxyl groups of the polyol, and 120 to 1 is added.
When the reaction was carried out at 30 ° C. for 2.5 hours while distilling off methanol, the viscosity was 5.0 Pa · s. Then, allyl chloride was added in an amount 1.2 times as much as sodium methoxide, and the end was allylated to give a hydroxyl value (OHV (me
q / g)) and iodine value (IV (meq / g)) were measured, and the allylation rate was measured by (Equation 2).
%Met.

Allylation rate (%) = {IV / (OHV + IV)} × 100 (Equation 2) Example 2 When h = 0.30H as shown in FIGS. 1 and 2, the blade diameter is relative to the tank diameter. Is 0.7 and the total height of the stirring blades is 1.40 with respect to the liquid surface, and the baffle width is 0.0 with respect to the tank diameter D.
A polyoxypropylene polyol with sufficient water removed was charged into a reaction tank equipped with four baffles having a size of 8D and a gap of 0.02D.
Viscosity at 0 ℃ is 0.32P as measured by B-type viscometer
At the time of introducing an unsaturated group at the terminal of a.s), 1.2 times equivalent of sodium methoxide (28% methanol solution) is added to the total amount of hydroxyl groups of the polyol, and 120 to 13
When the reaction was carried out at 0 ° C. for 2.5 hours while distilling off methanol, the viscosity was 5.2 Pa · s. After this,
Allyl chloride was added in an amount 1.2 times that of sodium methoxide, and the end was allylated to give a hydroxyl value (OHV (meq /
g)) and iodine value (IV (meq / g)),
When the allylation rate was measured by (Equation 2), it was 92%. Example 3 As shown in FIG. 1 and FIG. 2, stirring was performed with h = 0.30H, the blade diameter was 0.7 with respect to the tank diameter, and the total height of the stirring blades was 1.40 with respect to the liquid surface. Baffle width 0.0 for blade and tank diameter D
A polyoxypropylene polyol with sufficient water removed was charged into a reaction tank equipped with four baffles having a size of 8D and a gap of 0.02D.
Viscosity at 0 ℃ is 0.32P as measured by B-type viscometer
When introducing an unsaturated group to the terminal of a.s), 1.2 times equivalent of sodium methoxide (28% methanol solution) is added to the total amount of hydroxyl groups of the polyol, and 120 to 1 is added.
When the reaction was carried out at 30 ° C. for 3.5 hours while distilling off methanol, the viscosity was 7.8 Pa · s. Then, allyl chloride was added in an amount 1.2 times as much as sodium methoxide, and the end was allylated to give a hydroxyl value (OHV (me
q / g)) and iodine value (IV (meq / g)) were measured, and the allylation rate was measured by (Equation 2).
%Met. Comparative Example 1 As shown in FIGS. 3 and 4 described in JP-A-2-187137, there are three stages of stirring blades with h = 0.1H and a blade diameter of 0.95 with respect to the tank diameter. It has an inclined paddle blade of 0.5 and the total blade height of the stirring blade is 0.
No. 4 stirrer blade, 0.1 for tank diameter D in the part without stirrer blade
A reaction vessel equipped with four baffles of D was charged with polyoxypropylene polyol from which water was sufficiently removed, and the end of polyoxypropylene polyol (viscosity at 130 ° C. was 0.32 Pa · s measured by a B-type viscometer). At the time of introducing an unsaturated group into the above, 1.2 times equivalent of sodium methoxide was added to the total amount of hydroxyl groups of the polyol,
When the reaction was carried out at 120 to 130 ° C. for 2.5 hours while distilling off methanol, the viscosity was 3.5 Pa · s. After this, allyl chloride was added to 1.
Double the amount of the charged end is allylated to give a hydroxyl value (OH
V (meq / g)) and iodine value (IV (meq / g))
Was measured and the allylation rate was measured by (Equation 2), and it was 86%.

[0032]

According to the present invention, in the method for alkoxidizing the ends of polyether polyols, a vacuum devolatilization facility is provided, and a stirring shaft rotatable from outside the tank is installed at the center, and a flat blade is provided on the shaft. By using the reaction tank equipped with, it is possible to react to a sufficient reaction rate in a relatively short time without adding extra equipment or extras to increase the rate of the terminal alkoxide reaction. Became.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional side view of Examples 1, 2, and 3 of the present invention.

FIG. 2 is a schematic cross-sectional plan view of Examples 1, 2, and 3 of the present invention.

FIG. 3 is a schematic vertical sectional side view of a stirring blade of Japanese Patent Laid-Open No. 2-187137.

FIG. 4 is a schematic cross-sectional plan view of a stirring blade of Japanese Patent Laid-Open No. 2-187137.

[Explanation of symbols] 1 stirring shaft 2 liquid level 3 Upper stage comb-shaped wings 4 Comb-shaped wings in the middle stage 5 Lower flat blade 6 baffles 7 Surface stirring blade 8 Compound stirring blade H liquid depth h Lower wing height D tank diameter

Claims (3)

[Claims] 1. A method for alkoxidizing a hydroxyl group terminal of a polyether polyol by reacting a polyether polyol with an alkali metal alkoxide, which has a vacuum devolatilization facility and is provided with a stirring shaft from outside the tank, On the shaft, at the bottom of the reaction tank, the blade height was 0.
A method for alkoxide conversion of polyether polyols, characterized in that a reaction tank having a stirring blade having a blade diameter of 25 or more and a blade diameter of 0.35 or more with respect to the tank diameter is used. 2. The method according to claim 1, wherein the stirring blade has one or a plurality of blades or stirring blades, and the total height of the stirring blades is 0.8 or more with respect to the liquid surface. . 3. The stirring blade has flat plate blades arranged at the bottom of the reaction tank at the lowermost stage, and further comb-shaped blades mounted at the middle and upper stages, with respect to the flat plate blades at the lowermost stage. And the adjacent middle-stage comb-shaped blades are arranged at a crossing angle of less than 90 degrees ahead of the rotation direction, and the lowermost flat-plate blade and the upper-stage adjacent middle-stage comb-shaped blades are arranged. Has an overlap in the axial direction, and for the comb-shaped blade located in the middle stage, 90
Placed ahead of the direction of rotation with a crossing angle of less than degrees,
3. The method according to claim 1, wherein the middle comb blade and the upper comb blade that is adjacent to the middle comb blade have an axial overlap.