JPS6044288B2 - Method for producing glycol monoether - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for producing glycol monoethers using a novel catalyst.

Conventionally, as an industrial method for producing glycol monoether, which has a wide range of uses as a solvent and a reaction solvent, a method has been adopted in which an olefin oxide is produced from an olefin and a corresponding alcohol is added thereto.

However, in view of the recent petrochemical situation, methods of obtaining glycol monoether from raw materials other than olefins are being considered. One such method is to react acetal with carbon monoxide and hydrogen using cobalt carbonyl as a catalyst (German Patent No. 875,802).
and No. 89094). However, this method has the drawback of low selectivity for glycol monoethers. Furthermore, cobalt carbonyl is separated when glycol monoether is separated by distillation from the reaction product liquid, making it impossible to recycle the catalyst. As a result of studying improvements to this method, the present inventors found that when a trivalent organic phosphorus compound such as tertiary phosphine is used in combination with cobalt carbonyl in the reaction, the selectivity of glycol monoether is improved. I found out.

It has also been found that by doing so, the catalyst is stabilized and does not decompose when glycol monoether is distilled and separated from the reaction product liquid, so that it can be recycled. The present invention was completed based on this knowledge, and in the presence of a catalyst containing cobalt and tertiary phosphine,
General formula A1OCHR^3OR^2 [In the formula, R^” and R
^2 represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and R^゜ represents hydrogen or a methyl group.

] or 2 General formula R^'C
A polymer of aldehyde represented by HO [in the formula, R^゜ is the same as above], anoleconole represented by the general formula R^"OH [in the formula, R^" is the same as above], carbon monoxide and hydrogen A method for producing a glycol monoether, which comprises reacting the following.

To explain the present invention in more detail, the present invention is based on the general formula [where R1 and R2 represent an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and R3 represents hydrogen or a methyl group.

] can be used as a raw material.
According to the method of the present invention, industrially important ethylene glycol monoether is produced from formaldehyde acetal in the following manner. Other by-products include ROCH
3 ROCH2CH2ORROCH2CH2OCH2CH2
Ethers such as OHROCH2CH(0R)ClI2OH are produced.

The method of the present invention can also be carried out using a specific compound corresponding to the acetal as a raw material instead of the acetal.

That is, the acetal is an aldehyde represented by the general formula R3CHO [wherein R3 is the same as in the above formula (1)] and an alcohol represented by the general formula RlOH [wherein R1 is the same as in the above formula (1)]. However, in the method of the present invention, a polymer of the aldehyde that produces the above aldehyde under the reaction conditions and the above alcohol can also be used as raw materials.

Examples of the aldehyde polymer include paraformaldehyde and trioxane. When an aldehyde polymer and alcohol are used instead of acetal, they can be used in any ratio, but usually 0.01 to 1 alcohol per mole of aldehyde monomer.
00 mol, preferably in the range of 0.1 to 50 mol.
The ratio of carbon monoxide and hydrogen is also arbitrary, but in order to increase the reaction rate, 0.1 hydrogen per mol of carbon monoxide is used.
A range of 10 moles is preferred. The mixed gas of carbon monoxide and hydrogen may contain an inert gas such as methane, argon, or nitrogen. The present invention is carried out using a trivalent organic phosphorus compound and a cobalt compound as a catalyst.

As the cobalt compound, cobalt carbonyl or a compound capable of forming cobalt carbonyl under the reaction conditions is used. In either case, the cobalt compound and the trivalent organic phosphorus compound are thought to exist in the form of a complex in which carbon monoxide and the organic phosphorus compound are coordinated with cobalt under the reaction conditions. The cobalt compound and the trivalent organic phosphorus compound may form a complex in advance and introduce it into the reaction system, or the phosphorus compound and the cobalt compound may be introduced into the reaction system separately and form a complex under the reaction conditions. may be formed. Examples of complexes that can be prepared in advance include HCO(CO)3(R3P), which is produced by a well-known method.
, CO2(CO)6(R3P)2, and the like. When a trivalent phosphorus compound and a cobalt compound are separately introduced into the reaction system, dicobalt octacarbonyl is most typically used.

Also, cobalt compounds capable of forming cobalt carbonyl under the reaction conditions, such as cobalt metal, organic acid salts of cobalt such as cobalt oxide, cobalt acetate, and cobalt laurate, and inorganic salts of cobalt such as cobalt nitrate, cobalt sulfate, and cobalt halides. etc. are also used. Tertiary phosphine is used as the trivalent organic phosphorus compound used in combination with the cobalt compound.

As the tertiary phosphine, tributylphosphine, trioctylphosphine, triisopropylphosphine and other alkylphosphines, arylphosphines such as triphenylphosphine and tritolylphosphine, and cycloalkylphosphines such as tricyclohexylphosphine are used.

Also used are mixed phosphines having different alkyl groups or alkyl and aryl groups. In addition, screws (
Phosphines having multiple phosphorus atoms, such as diphenylphosphino)ethane, are also used. In fact, phosphines having multiple phosphorus atoms and thus acting as polydentate ligands generally give better reaction results than simple phosphines having only one phosphate atom. The ratio of tertiary phosphine to cobalt compound is usually in the range of 0.1 to 100 phosphorus/cobalt atomic ratio.

However, under the same reaction conditions, a higher proportion of phosphorus generally reduces the reaction rate and therefore requires a higher reaction pressure. Furthermore, if the proportion of phosphorus is small, the stability of the catalyst is insufficient. Therefore, from these points, phosphorus/cobaltoni 0
- The range of 3 to 10 is more preferable. The amount of the catalyst used varies depending on the tertiary phosphine used, the cobalt compound, the acetal used as the raw material, the reaction conditions, etc., but it is usually 10-1 to 10-1 cobalt atoms per gram mole of acetal (or aldehyde monomer). In the range of 10-5 gram atoms.

Of course, even if the amount of catalyst is less than this, the reaction will proceed sufficiently if the reaction time is increased. Furthermore, even if the amount of catalyst is greater than this, the reaction will not be hindered in any way. The process of the present invention can be carried out without a solvent, but can also be carried out in the presence of an inert solvent if desired.

For example, ethers such as diethyl ether, dioxane, and diphenyl ether, esters such as methyl acetate and methyl formate, ketones such as acetone and diethyl ketone, aromatic hydrocarbons such as benzene and toluene, and aliphatic carbons such as hexane and heptane. Examples include hydrogen and alcohols such as methanol and butanol. When alcohols are used as solvents, it is particularly preferable to use alcohols that are constituents of acetal. In general, it is preferable to use a solvent with a boiling point higher than that of the glycol monoether produced in the reaction in view of the cyclic use of the catalyst. However, even with a low boiling point solvent, the catalyst can be recycled by accumulating high boiling point substances or by leaving a portion of the glycol monoether. The method of the present invention can be suitably carried out using either a batch method or a continuous reaction method.

The reaction is usually carried out under pressure. Especially 10-100
It is preferable to carry out in the range of 0 kgIdG. The reaction temperature is usually 50 to 300°C, preferably 100 to 250°C. After the reaction is completed, the produced glycol monoether can be easily separated by a known method such as distillation, and the catalyst containing phosphorus and cobalt can be recycled and reused as it is while remaining dissolved. As detailed above, according to the method of the present invention, glycol monoethers can be produced from acetal with good selectivity, and the catalyst can be reused while being dissolved in the reaction medium.

Hereinafter, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to the following examples.

In each example, a stainless steel autoclave with a capacity of 200 ml and equipped with an electromagnetic vertical stirrer was used as the reactor.

Examples 1 to 6 and Comparative Example 1 Formaldehyde di-n-butyl acetal (CH2
(0Bu-n)2) 16 da(a). 1 MOl), dicobalt octacarbonyl CO2 (CO) 80.682y (
2.07 TL, m0I), a trivalent organic phosphorus compound shown in Table 1 (2.0 mm 0, and 33 ml of toluene were charged into a reactor, the interior of the reactor was replaced with argon, and then carbon monoxide was pressurized to a predetermined pressure. The temperature was raised to 160°C.

Thereafter, hydrogen was injected under pressure to a certain constant pressure to carry out the reaction. After the reaction was continued until no gas absorption was observed, the product was analyzed by gas chromatography. Butyl cellosolve n-BuOCll2 for acetal
The yield of CH2OH is shown in Table 1.

In addition, the conversion rate of formaldehyde di-n-butyl acetal was 9 in all Examples 1-6 and Comparative Example 1.
It was over 9%. In addition to butyl cellosolve, n-
BuOCH3, n-BUOCH2CH2OCH2CH2
OH. ．． n-BuOCH2CH) (0Bu-n)CH2
A total of 25-35% OH was produced.

Example 7 Acetaldehyde diethyl acetal CH3C
H(0Et)20.1m01, dicobalt octalcarbonyl CO2(CO)82Trt, m011 bis(diphenylphosphino)ethaneφ2PC112CH2Pφ2
Charge 27TLm01 and 30ml of toluene into a reactor, pressurize carbon monoxide to 55kgIc71fG, and heat to 160°C.
The temperature rose to .

The pressure after increasing the temperature was 80k9 CIiG. 160k91d of hydrogen was further pressurized into this, resulting in a total pressure of 240kgI.
The reaction was started with cItG. The reaction was continued for 6 hours until gas absorption completely stopped, and the reaction product was analyzed by gas chromatography. As a result, propylene glycol-β-monoethyl ether CH3CH(0Et)CH2
0.0422 rT101 of OH was produced (yield 42.2%).

Example 8 In Example 7, formaldehyde diisobutyl acetal CH2(0Bu-1)2 was used as the acetal.
The experiment was conducted in the same manner as in Example 8, except that the reaction time was 8 hours. As a result, isobutylcellosolve i-BuOCH2CH2OH was 0.0556 m01 (yield: 5
5.6%).

Example 9 Rose formaldehyde 3y (formaldehyde 0.1m
01 equivalent), n-butanol n-BuOH46ml (approximately 0.5m01), dicobalt octacarbonyl CO2 (
CO) 82.0 mm01 and tri-n-butylphosphine BU3P2. After charging OrrL, mOl into a reactor and purging it with argon, gas having a composition ratio of H2/CO=1.6 was pressurized to 180k91cILG.

The temperature was raised to 160'C and the reaction was continued for 3 hours until gas absorption completely stopped.

As a result, butyl cellosolve n-BuOCH2CH2O
0.051 m01 (yield 51%) of H was produced.
Comparative Example 2 Except for not adding tri-n-butylphosphine. conducted an experiment similar to Example 9.

As a result, butyl cellosolve was obtained with a yield of 42%. Example 10 Formaldehyde di-n-butyl acetal C1 (2(0Bu-n) 20.1m01, dicobalt octacarbonyl CO2 (CO) 82.0mm01
Bis(diphenylphosphino)ethaneφ2PCH2CH
2Pφ20.796y (2.07T1, m01) and 30ml of diphenyl ether were charged into a reactor, and after purging the inside of the reactor with argon, carbon monoxide was pressurized to 56kg1cILG, and the temperature was raised to 160°C.

The pressure showed 80k9 CItG. Hydrogen was further pressurized at 160 k9 nod to start the reaction at a total pressure of 240 k91 dG. 5 until no gas absorption is observed.
The reaction was continued for an hour. After the reaction, the yield of the produced "butyl cellosolve" was determined by gas chromatography and Example 10
And so. As a result of analysis by gas chromatography, the yield of butyl cellosolve was 67%.

The reaction solution was distilled under reduced pressure under a nitrogen atmosphere.

Temperature 120℃, degree of vacuum 5T1! The butyl cellosolve was completely distilled off with MHg, leaving a dark brown catalyst-containing diphenyl ether solution in the distillation pot. The experiment was conducted in the same manner as the previous experiment except that diphenyl ether was added to this distillation residue solution and used as a 30 ml catalyst solution.

The circulation experiment of this catalyst solution was repeated in the same manner.

The yield of butyl cellosolve is shown in Table 2. Comparative Example 3 In Example 10, an experiment was conducted in the same manner as in Example 11 except that bis(diphenylphosphino)ethane was not added.

Claims (1)

[Claims] 1. In the presence of a catalyst containing cobalt and tertiary phosphine, (1) the general formula R^1OCHR^3OR^2 [wherein,
R^1 and R^2 represent an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and R^3 represents hydrogen or a methyl group. ] or (2) general formula R^3
A polymer of aldehyde represented by CHO [in the formula, R^3 is the same as above], an alcohol represented by the general formula R^1OH [in the formula, R^1 is the same as above], and carbon monoxide and hydrogen. A method for producing glycol monoether, which comprises reacting.