JPH06279581A - Production of polyesther terminated by alcoholate - Google Patents

Abstract

PURPOSE:To enhance the conversion of an alkali metal in the treatment of a polyether having a hydroxyl value of 70 or lower with the metal to produce an alcoholate-terminated polyether, by improving the solubility of the metal in the polyether. CONSTITUTION:An alkali metal is incorporated into a polyether along with a 1-4C monohydric alcohol to dissolve the metal, the amount of the alcohol being 0.5-10.0mol per mol of the metal. The metal is reacted with terminal hydroxyl groups of the polyether to convert the polyether into an alcoholate. The alcohol is then removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for producing terminally alcoholated polyethers by treating polyethers having a hydroxyl value of 70 or less with an alkali metal.

[0002]

Polyethers obtained by subjecting an initiator to a ring-opening reaction of monoepoxide such as alkylene oxide are widely used as raw materials for synthetic resins such as polyurethane, surfactants, lubricants and other applications. There is.

The initiator is a hydroxyl group-containing compound represented as follows. A- (H) _n A: a residue of a hydroxyl group-containing compound from which a hydrogen atom of a hydroxyl group has been removed n: an integer of 1 or more as the initiator, for example, monohydric alcohol, polyhydric alcohol, monohydric phenol, polyhydric phenol, etc. There is. A compound having a hydroxyalkylamino group (alkanolamines-alkylene oxide adduct, etc.) is also used as the initiator. further,
Polyethers obtained by reacting the above initiator with monoepoxide are also used as the initiator. In addition, polyethers obtained by alcoholating the terminals may be used as an intermediate to further modify the terminals such as silylation.

Polyethers are the following compounds obtained by subjecting the above initiators to a ring-opening reaction of monoepoxide. A-[(RO) _m H] _n R: monoepoxide ring-opening unit n, m: an integer of 1 or more

The catalyst for producing polyethers is
An alkali catalyst such as potassium hydroxide, sodium hydroxide or amines, an acid catalyst such as boron trifluoride, a complex metal cyanide, a metal complex catalyst such as metal porphyrin or the like is used.

[0006]

As a method of alcoholating the terminal hydroxyl groups of polyethers having a hydroxyl value of 70 or less, there is a method of alcoholating the terminals with an alkali metal hydroxide, but the reactivity is low. Therefore, it has been impossible to increase the reaction rate of the alkali metal hydroxide to 50% or more.

Alkali metal hydrides have high reactivity and therefore have sufficient ability as alcoholating agents for the terminal hydroxyl groups of polyethers, but they are unstable in air and easily generate heat to decompose. High handling risk and high cost.

Alcoholates such as methylates of alkali metals can also be used as the above-mentioned alcoholating agents, but it is necessary to react the alkali metal with an excess of alcohol for a long time to synthesize, and commercially available products are expensive. Becomes The above alcoholates are powders (purity: 95
%) Or more, the workability is poor, and the alcohol solution (20 to 30%) is dangerous to handle, and the volume is large, so the workability is poor.

Alkali metals are highly reactive and cost-resistant to industrial production and are suitable as alcoholating agents, but they have a low solubility in polyethers having a hydroxyl value of 70 or less, and therefore have a long reaction time. There is a problem that it takes time and unreacted alkali metal remains.

Therefore, the present invention improves the solubility of an alkali metal in a polyether in a method for producing a terminal alcoholated polyether by treating a polyether having a hydroxyl value of 70 or less with an alkali metal, An object of the present invention is to provide a method for producing a terminal alcoholated polyether having an increased reaction rate of an alkali metal.

[0011]

The present invention has a hydroxyl value of 70.
The following polyethers are treated with an alkali metal to produce a terminal alcoholated polyether, and a monoalcohol having 1 to 4 carbon atoms is added in an amount of 0.5 to 10.0 molar equivalents with respect to the alkali metal. This is a method for producing terminally alcoholated polyethers, which comprises dissolving a metal and alcoholating the terminal hydroxyl groups of the polyethers, and then removing the monoalcohol.

[0012]

In the present invention, when a polyether having a hydroxyl value of 70 or less, preferably a hydroxyl value of 5 to 35 is treated with an alkali metal, a monoalcohol having 1 to 4 carbon atoms is added to dissolve the alkali metal. And as a result, the terminal hydroxyl groups of the polyethers are reacted with an alkali metal at a high reaction rate to facilitate the production of the terminal alcoholated polyethers.

As the monoalcohol having 1 to 4 carbon atoms, methanol, ethanol, propanol, butanol, etc. are used, and the addition amount of monoalcohol is 0.5 to 10.0 molar equivalents with respect to the alkali metal, preferably. Is suitably 1.0 to 5.0 molar equivalents. If the carbon number of the monoalcohol is 5 or more, or if the addition amount of the monoalcohol is less than 0.5 molar equivalent, the alkali metal cannot be reliably dissolved. Further, since these monoalcohols have a low boiling point, it is extremely easy to remove them after the completion of the alcoholation reaction, but if they exceed 10.0 molar equivalents, it becomes difficult to remove the monoalcohols. The melting temperature of the alkali metal is 25 to 150 ° C., preferably 70 to
130 ° C. is suitable, and the temperature during removal of the monoalcohol after completion of the alcoholation reaction is suitably 70 to 130 ° C.

According to the method of the present invention, the used alkali metal can be reacted at a reaction rate of 95% or more, and the content of the remaining alkali metal can be suppressed to a very low level. In addition, the terminal hydroxyl group of polyethers is 5
It is also possible to volatilize arbitrarily in the range of 100%.

[0015]

EXAMPLE The following polyalkylene ether polyol was subjected to alcoholation reaction of terminal hydroxyl groups using sodium metal. Polyol A: Polyoxypropylene triol having a molecular weight of 5000 and a hydroxyl value of 33.7. Polyol B: Polyoxypropylene diol having a molecular weight of 10,000 and a hydroxyl value of 11.2. Polyol C: molecular weight 20000, hydroxyl value 11.2,
Propylene oxide, ethylene oxide, and
Polyoxyethylene propylene butylene tetraol obtained by randomly polymerizing 1,2-butylene oxide at a ratio of 80/10/10 by weight.

Example 1 To 1000 g of polyol A, 1.0 equivalent of sodium metal / hydroxyl group and 2.
After adding 0 equivalent / sodium and stirring the mixture in a closed autoclave at 70 ° C. for 1.0 hour to carry out the alcoholation reaction, methanol was removed at the same temperature and 20 Torr.
The appearance of the obtained modified polyol before filtration was observed, the modified polyol was filtered at room temperature to remove solid impurities, and the terminal alcoholation ratio was measured by acid titration. The results shown in Table 1 were obtained. .

Comparative Example 1 A modified polyol was obtained in the same manner as in Example 1 except that the addition of methanol was omitted.
The results of Table 1 were obtained in the same manner as in Example 1.

Example 2 To 1000 g of polyol B, 1.0 equivalent of sodium metal / hydroxyl group and 1.
After 8 equivalents / sodium were added and the mixture was stirred at 85 ° C. for 1.5 hours in a closed autoclave to carry out the alcoholation reaction, ethanol was removed at the same temperature and 20 Torr.
The results of Table 1 were obtained for the obtained modified polyol in the same manner as in Example 1.

Comparative Example 2 A modified polyol was obtained in the same manner as in Example 2 except that the addition of ethanol was omitted.
The results of Table 1 were obtained in the same manner as in Example 1.

Example 3 To 1000 g of polyol C, 1.02 equivalents of metal sodium / hydroxyl group and 3.0 equivalents / sodium of 2-propanol were added, and the mixture was stirred at 85 ° C. for 1.0 hour in a closed autoclave to give an alcoholate. After carrying out the chemical reaction, 2-propanol was removed at the same temperature and 20 Torr. The results of Table 1 were obtained for the obtained modified polyol in the same manner as in Example 1.

Comparative Example 3 A modified polyol was obtained in the same manner as in Example 3 except that 3.0 equivalents / sodium of n-octyl alcohol was added instead of 2-propanol. When the appearance of the obtained modified polyol before filtration was observed, as shown in Table 1, there was slight gray turbidity, and the modified polyol was filtered at room temperature to remove solid impurities,
When the terminal alcoholation rate was measured by acid titration, 0.2% of the polyol C was only alcoholized. Therefore, when the end groups were analyzed by the H-NMR method, it was found that 25% of n-octyl alcohol remained in the form of alcoholate.

Comparative Example 4 A modified polyol was obtained in the same manner as in Example 3 except that 0.2 equivalent of 2-propanol / sodium was added, and the results in Table 1 were obtained in the same manner as in Example 1. It was

[0023]

[Table 1]

The modified polyols obtained in Examples 1 to 3 are all transparent, and it can be seen that all the alkali metals have reacted. On the other hand, gray foreign substances were observed in the modified polyols obtained in Comparative Examples 1 to 4, and when the foreign substances were filtered and analyzed, they were unreacted alkali metals.

[0025]

Industrial Applicability According to the present invention, by adopting the above-mentioned constitution, it becomes possible to produce a terminal alcoholated polyol without containing unreacted alkali metal and with a high alcoholating rate.

Claims (3)

[Claims] 1. A process for producing a terminal alcoholated polyether in which a polyether having a hydroxyl value of 70 or less is treated with an alkali metal, wherein a monoalcohol having 1 to 4 carbon atoms is added in an amount of 0.5 to 10 relative to the alkali metal. A method for producing a terminal-alcoholated polyether, which comprises blending 0.0 molar equivalents to dissolve an alkali metal to alcoholate a terminal hydroxyl group of a polyether and then remove a monoalcohol. 2. The method for producing a terminal alcoholated polyether according to claim 1, wherein the reaction rate of the alkali metal used is 95% or more. 3. A polyether having 5 to 100 terminal hydroxyl groups.
% Is alcoholated, The method for producing a terminal alcoholated polyether according to claim 1 or 2, which is characterized in that.