JPS6045166B2 - Method for producing 3-(β-hydroxyethyl)butenols - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing 3-(β-hydroxyethyl)phanols.

More specifically, the present invention relates to a method for producing 3-(β-hydroxyethyl)phanols represented by the following formulas (I) and (■) from 3-methyl-3-buten-1-ol and formaldehyde. CH.

OHp, ,CH2・,・G゛CH2OH (I) Cf(2NOH, -!'”・-6, (Π) 3-Methyl-3-buten-1-ol or its acetate ester reacts with formaldehyde to form 3- It has been known for a long time to produce (β-hydroxyethyl) phanol compounds (J.

Am. In the method, the objective 3-(β-
The yield of hydroxyethyl) phanol compound is low and is not industrially satisfactory.

Both 3-methyl-3-buten-1-ol and the product 3-(β-hydroxyethyl)phanols are β-hydroxyolefins or substituted products thereof, and these are not necessarily thermally stable.

β-Hydroxyolefins are thermally decomposed into olefins and formaldehyde as shown by the following formula (see Minoru Imoto et al., eds., "Formaldehyde - Its Chemistry and Applications", p. 129 (published by Asakura Shoten in 1939)). Especially under acidic conditions, these β-hydroxyolefins are extremely unstable. In addition, the product represented by the above formula (■) is also an allylic alcohol, so it is unstable under acidic conditions.
Easily converted to corresponding aldehydes and hydrocarbons through rearrangement, dehydration, and other reactions.

Further, the product represented by the above formula (1) and the starting material 3
-Methyl-3-buten-1-ol is also as shown in the following formula,
Under acidic conditions, it converts to allylic alcohol, which also undergoes rearrangement, dehydration, and other reactions. (R = methyl, β-hydroxyethyl group) Furthermore, formaldehyde is not necessarily stable at high temperatures, and is known to produce formic acid, a highly corrosive acid, through a thermal disproportionation reaction (Tokuko Sho). No. 37-10652 and "Formaldehyde Its Chemistry and Applications", pages 44 and 459).

Therefore, when 3-methyl-3-buten-1-ol and formaldehyde are reacted at high temperatures in the presence or absence of an acidic catalyst, various side reactions occur, resulting in the production of 3-(β- It is difficult to obtain hydroxyethyl)butenols in a good yield of 5. In the reaction of thermally adding formaldehyde to an olefinic double bond to obtain β-hydroxyalkenes, an improved method for obtaining the target product in good yield is achieved by neutralizing the formic acid produced. Several methods have been proposed to maintain neutrality.

For example, a method in which a basic substance containing a salt of an acid weaker than formic acid is added to the reaction system (Japanese Patent Publication No. 47-513), or a buffering agent is added to maintain the pH of the reaction system at 4 to 7. A method (Japanese Unexamined Patent Publication No. 50-17111003) is known. However, if an alkaline substance is added to the reaction system, formaldehyde will be consumed by Cannitzaro reaction and other processes, which is not preferable. The present inventors solved the above-mentioned problems and
As a result of intensive research into a method for obtaining butenols in good yield, the present invention was achieved.

That is, the present inventors obtained 3-methyl-3-butene-1-
It has been found that if ol and formaldehyde are reacted in the presence of tertiary phosphine, the production of formic acid is suppressed and the target product, 3-(β-hydroxyethyl)butenols, can be obtained in high yield. Although the tertiary phosphine, which is an additive in the method of the present invention, has almost no effect of neutralizing the formic acid produced, its addition results in decomposition of raw materials and products, and other side reactions. is suppressed and the product yield is improved.

The reason for this is presumed to be that the tertiary phosphine suppresses the by-production of formic acid itself. This action of tertiary phosphine is surprising considering the conventional technical knowledge. The tertiary phosphine used in the process of the invention has the general formula PRR"R" (where R,,R"
, R'' can be an alkyl group, a cycloalkyl group, an aryl group or an aralkyl group which may have the same or different substituents.

Among these tertiary phosphines, R. Tertiary phosphine in which sR'' and R'' are the same group is preferred in terms of ease of availability and other points, and representative compounds thereof include triethylphosphine, tributylphosphine, tricyclohexylphosphine, triphenylphosphine, and tritolylphosphine. , tribenzylphosphine, etc.
Particularly preferred are tri-n-butylphosphine and triphenylphosphine. Moreover, two or more types of tertiary phosphines can also be used as a mixture. The amount of tertiary phosphine added is 0.01 to 10% of the formaldehyde charged.
mol %, preferably 0.1 to 5 mol %.

The formaldehyde used in the present invention may be not only a formaldehyde aqueous solution but also a compound that generates formaldehyde under reaction conditions.

Examples of such formaldehyde-producing compounds include:
For example, mention may be made of paraformaldehyde, trioxane, polyoxymethylene and hemiformals of primary alkanols having 1 to 20 carbon atoms. The presence of water when using an aqueous formaldehyde solution does not necessarily inhibit the reaction, but if the water content in the reaction system is 3% by filtration.
Therefore, the formaldehyde concentration in the formaldehyde aqueous solution used is preferably selected so that the water content of the reaction system is 3% by volume or less. If the moisture content exceeds 30%, the amount of water to be separated from the reaction mixture increases, which is not only disadvantageous in terms of energy, but also a significant decrease in the yield of 3-(β-hydroxyethyl)butenol. . The molar ratio of raw materials 3-methyl-3-buten-1-ol and formaldehyde to be used in carrying out the present invention has a close relationship with the reaction results. Usually, it is preferable to increase the conversion rate of formaldehyde by using an excess of 3-methyl-3-buten-1-ol, which also improves the selectivity to 3-(β-hydroxyethyl)butenol based on the reacted formaldehyde. do. Generally, 3-methyl-3-buten-1-ol is used in a ratio of 2 to 10f8 moles relative to formaldehyde. The reaction temperature is 1
The temperature range is preferably 80 to 250°C, particularly preferably 190 to 220°C.

If the reaction temperature is too low, the reaction rate will be low, and if it is too high, side reactions will increase. The reaction time is appropriately selected depending on other reaction conditions, such as the reaction temperature, but is usually 1 to 1 hour, and under preferred reaction conditions, 1 to 5 hours is appropriate. The reaction pressure is not particularly limited as long as it maintains the reaction system in a liquid phase at the reaction temperature, but usually the vapor pressure of the reaction mixture at the reaction temperature is used. The reaction can also be carried out under pressure with an inert gas such as nitrogen gas, but this does not provide any particular benefit. Although the method of the present invention does not preclude the use of solvents or diluents, as mentioned above, since 3-methyl-3-buten-1-ol is used in excess relative to formaldehyde, excess 3-methyl-3-buten-1-ol is used. -Ol acts as a solvent.

However, hydrocarbon, ether, and alcohol solvents that do not harm the reaction, such as hexane, octane, cyclohexane, benzene, toluene, diethyl ether, tetrahydrofuran, dioxane, methanol, propanol, and butanol, may be used alone or in mixtures. good. There is no particular restriction on the amount of solvent used, but since using more solvent than necessary will reduce the reaction rate, the appropriate amount of solvent should be determined within an economical range in relation to other reaction conditions. selected within. The reaction of the present invention can be carried out in either a liquid phase continuous system or a liquid phase batch system.

3-(β-hydroxy-7diethyl)butenol obtained by the method of the present invention is useful as an intermediate for various synthetic products, and is used, for example, as a diol component in polyurethanes, polyesters, etc., either as it is or after hydrogenation.

Hereinafter, the present invention will be specifically explained using examples.

Example 1 Internal volume 30 with pressure gauge, safety valve and electromagnetic stirring device
Commercially available 3% formalin 12.1y containing 8% by weight of methanol [contains 0.149 mol of formaldehyde and 0.03 mol% of free formic acid (based on formaldehyde)], 3-methyl-3 in a ml stainless steel autoclave. −
Buten-1-ol 50f (0.581 mol) and triphenylphosphine 0.38f (0.00145 mol) were charged, and after purging the inside of the autoclave with nitrogen, the above mixture was heated and reacted at 200°C for 4 hours while stirring. Ta.

The obtained reaction product was analyzed by gas chromatography.
Further, the reaction rate of formaldehyde was measured by the sodium sulfite method. The reaction rate of formaldehyde is 92%,
The selectivity of 3-(β-hydroxyethyl)butenol based on the reacted formaldehyde is 81%, and the selectivity of 3-(β-hydroxyethyl)butenol is 81% for the compound of formula (■) in the product.
The production ratio of the compound represented by 1) was 1.39. In addition, free formic acid was detected at 0.9 mol% based on the formaldehyde charged, and 3% by gas chromatography.
-Formic acid ester of methyl-3-buten-1-ol was detected at 1.2 mol % based on the formaldehyde charged. Example 2 Tri-n-butylphosphine [(n-Bu
)3P] was used, the same reactor as in Example 1 was used, and the reaction was carried out in the same manner as in Example 1 using the reaction conditions shown in Table 1.

The results obtained are shown in Table 1. Comparative Example 1 A reaction was carried out in exactly the same manner as in Example 1, except that triphenylphosphine was not used.

As a result, the reaction rate of formaldehyde was 92%,
The selectivity of 3-(β-hydroxyethyl)butenol based on the reacted formaldehyde was 63%. In addition, free formic acid was detected at 1.5 mol% based on the formaldehyde charged, and other 3-
Formic acid ester of methyl-3-buten-1-ol was detected at 2.1 mol % based on the formaldehyde charged.
[(1)/(■)=1.68] Examples 3 to 7 Triphenylphosphine [abbreviated as Ph3P] was used as an additive, and commercially available 9% solid formaldehyde and 4heels were used as formaldehyde sources. The reaction was carried out in the same manner as in Example 1 using the same reactor as in Example 1 and the reaction conditions shown in Table 1, using % formalin by volume, 3% formalin by volume, and 1% formalin by volume. .

The results obtained are shown in Table 1. Reference example (thermal stability test of formalin) Formalin was placed in a 300 m1 electromagnetic stirring autoclave, and its thermal stability at 200°C under a nitrogen atmosphere was compared between a system with the addition of triphenylphosphine and a system without the addition.
At that time, the amount of formic acid and the amount of methyl formate were simultaneously investigated.

The results are shown in Table 2. The amounts of methanol and formic acid in the formalin used were as follows.

F-1: Formaldehyde concentration 3% by weight, methanol concentration 8% by weight, methyl formate concentration 0.11% by weight, formic acid 0.03 mol% (relative to formaldehyde) F
-2: Formaldehyde concentration 34% by weight, methanol concentration 1. Sill weight% Methyl formate concentration 0.0 heel weight%

Claims (1)

[Claims] 1. A method for producing 3-(β-hydroxyethyl)butenols, which comprises reacting 3-methyl-3-buten-1-ol and formaldehyde in the presence of tertiary phosphine.