JPS585171B2 - Fuhouwa alcohol - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing unsaturated alcohols.

More specifically, the present invention relates to a method for producing an unsaturated alcohol by reacting an olefin in which at least one hydrogen atom is bonded to at least one carbon atom adjacent to a double bond carbon atom with an aldehyde.

U.S. Patent No. 2,335,027 and Journal of the Arerican
Chemical 5ociety Volume 77 4666-
4668 (1955) describes a process for reacting olefins and saturated aldehydes in substantially stoichiometric amounts, i.e., with a molar ratio of olefin to saturated aldehyde of approximately 1, at temperatures in the range of 100 to 250°C. There is.

The specific methods described in such documents include, for example, 2
Inbutylene and formaldehyde at a temperature of 00℃,
3-Methyl-buten-3-ol-1 has been obtained in yields of up to 31 mol% by reacting inbutylene and formaldehyde in a ratio of 1.17:1.

On the other hand, even if the molar ratio of isobutylene and aldehyde is around 1, it is possible to improve the yield of unsaturated alcohol by adding a solvent or diluent, for example, Jou
rnal of the American Chemical
al 5ociety Volume 77 (1955) 78~
It is described on page 80.

That is, the molar ratio of isobutylene to formaldehyde is 1.
Even if the ratio is 5:1, 3-methylbuten-3-ol-1 and its acetic acid can be dissolved by adding a diluent consisting of formaldehyde, an equimolar amount of glacial acetic acid, and 0.2 times the molar amount of acetic anhydride at a reaction temperature of 190°C. Yields of esters are shown to be obtained in a total of 79% based on formaldehyde.

In addition, using tetrahydrofuran as a diluent, 300
A method for obtaining 3-methylbuten-3-ol-1 in a yield of 45 mol % from isobutylene and trioxane at 0.degree. C. has also been proposed (see Japanese Patent Publication No. 47-47362).

As is clear from the above, according to the conventional method, the maximum yield is only about 31% when no solvent or diluent is used, and a yield of 79% can only be obtained by using a special solvent. do not have.

Furthermore, if such a solvent is used and the reaction is carried out at a high temperature of 200° C. or higher, the corrosive effect of the solvent on the material of the reactor is extremely large, making it difficult to avoid the use of expensive special materials with corrosion resistance.

Furthermore, since such solvents or diluents are naturally contained in the reaction products, not only do they require complicated steps to separate the reaction products, but they also have an odor even if they are contained in trace amounts in the products. In order to synthesize terpenes or their derivatives effective as fragrances or food additives from the produced unsaturated alcohol, several stages of purification steps are essential to remove such odors.

Further, it is clear that the use of a large amount of solvent itself inevitably reduces the production amount per reactor.

As mentioned above, the use of solvents has various drawbacks, so although the production yield of unsaturated alcohols can be considerably increased, the production cost will not simply decrease, and in some cases may even increase. This industrial disadvantage could not be avoided.

The present inventors conducted research to overcome the above-mentioned drawbacks, and surprisingly found that when an olefin and an aldehyde are reacted in a specific ratio, substantially no reaction occurs without using any solvent or diluent. It has been found that even in the absence of a catalyst, results are obtained that are superior to the yields previously known as described in the above-mentioned publications.

That is, the present invention has been achieved based on such new findings, and is based on an olefin and an aldehyde in which at least one hydrogen atom is bonded to at least one carbon atom adjacent to a carbon atom of a double bond. An unsaturated alcohol characterized in that the mononuclear reaction is carried out without a solvent and under conditions satisfying the following formula (1) (n is the number of double bonds contained in the olefin): It is a manufacturing method.

The olefin used in the present invention has at least one hydrogen atom bonded to at least one carbon atom adjacent to a double bond carbon atom, and is specifically represented by the following formula.

Here, R1-R5 mean a hydrogen atom or a saturated or unsaturated hydrocarbon residue.

The hydrocarbon residue is preferably an alkyl group having 1 to 15 carbon atoms, particularly preferably 1 to 10 carbon atoms;
Cycloalkyl groups preferably consisting of 3 to 16, particularly preferably 5 to 8 carbon atoms and preferably 6 to 15
Aralkyl and aryl groups containing 1, particularly preferably 6 to 12 carbon atoms are used.

Furthermore, R2 and R5 can be used in the present invention even when they are bonded to each other and a double bond is present in the ring of a cyclic compound having 5 or more carbon atoms.

Particularly preferred hydrocarbon residues include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and pentyl groups, and cycloalkyl groups such as cyclopentyl, cyclohexyl, methylcyclopentyl, methylcyclohexyl, and ethylcyclohexyl groups. , aralkyl groups such as benzyl, methylbenzyl, ethylbenzyl, phenethyl groups,
Aryl Motokichi includes phenyl, methylphenyl,
Examples include dimethylphenyl and ethylphenyl groups.

Although it is also possible to contain an olefinic hydrocarbon group in R1-R5, the present invention does not contain an olefinic hydrocarbon group in R1-R5, that is, the double bond is
Preferably, olefins containing

In addition, when selecting the substituents (R1-R5) in the olefin used in the present invention, care should be taken to the structure of the substituents so as not to reduce the production selectivity of the target unsaturated alcohol. This is desirable.

Further, R1 to R5 may be either hydrogen atoms or the above-mentioned hydrocarbon residues independently of each other, and their ratio is arbitrary.

The aldehyde used in the present invention is preferably an aldehyde having 2 to 10 carbon atoms, particularly preferably formaldehyde.

Preferred aldehydes include alkyl aldehydes such as acetaldehyde, propionaldehyde and butyraldehyde, and cyclopertyl aldehyde.

Alicyclic aldehydes such as cyclohexylaldehyde and methylcyclohexylaldehyde, araliphatic aldehydes such as phenylacetaldehyde, and aromatic aldehydes such as benzaldehyde and tolualdehyde were used.

Such aldehydes may be used as monomers, or may be reacted as oligomers or polymers.

The monomer may be, for example, one synthesized by decomposing an oligomer or polymer using heat or a catalyst, or a compound such as a hydrate or acecool that can be decomposed using heat or a catalyst to produce a monomer. After decomposition and removal of water or alcohol other than the aldehyde monomer, it may be used in the reaction, but in either case no solvent or diluent is used.

As oligomers and polymers, trioxane, tetraoxymethylene, paraformaldehyde, polyoxymethylene, paraaldehyde, etc. are preferred, and these polymers may have an ester or ether atomic group at the end.

In the case of formaldehyde, it is particularly advantageous to use paraformaldehyde, since its stability, ease of handling and toxicity to humans are significantly superior to formaldehyde monomers.

This is due not only to the fact that formaldehyde is easily generated simply by heat treatment.

Further, paraformaldehyde is easily available as a commercial product, and can be used as is for the reaction.

In the present invention, when aldehyde is used as an oligomer or polymer, the number of moles thereof is treated as containing the number of moles of aldehyde generated when the aldehyde is decomposed.

For example, trioxane as 3 moles of aldehyde.

be handled.

In the present invention, the reaction does not use or require solvents or diluents.

The molar ratio of the olefin and aldehyde can be adjusted according to the formula (1) without using solvents or diluents such as a mixed solution of glacial acetic acid and acetic anhydride or tetrahydrofuran, which have been conventionally used to improve the yield. By maintaining a satisfactory ratio of unsaturated alcohols, unsaturated alcohols can be easily obtained in high yields in the temperature range of 150 to 400°C.

Even if a small amount of water, alcohol, or acid is contained in the raw material aldehyde, if the reaction is carried out under the above conditions, the desired unsaturated alcohol can be produced in high yield without completely removing these substances. can be obtained.

In the present invention, the molar ratio of the starting materials olefin and aldehyde is an important factor in obtaining the desired unsaturated alcohol in high yield.

As mentioned above, the reaction in the present invention is carried out substantially without using a solvent or diluent, and in that case, aldehyde (1
It is necessary to maintain the (mol) ratio of olefin to (mol) at 2n or more.

Here, it is the number of double bonds contained in the olefin, and particularly preferably, the double bond has at least one hydrogen atom bonded to at least one carbon atom adjacent to the carbon atom of the double bond. means something that is.

The preferred ratio of olefin to aldehyde is 3n or more, especially 4n or more, and by doing so, it becomes possible to obtain an unsaturated alcohol with extremely high yield and high purity.

When the molar ratio of the olefin and aldehyde is less than 2n, side-reactants other than the desired unsaturated alcohol are significantly produced, resulting in only a low yield and low purity unsaturated alcohol.

On the other hand, the upper limit of the molar ratio is not particularly limited, but is usually 1
00n or less, preferably 50n or less.

Therefore, in the present invention, it is important to maintain the molar ratio of the olefin and aldehyde without using a solvent or diluent, and these conditions together make it possible to produce a highly pure unsaturated alcohol in high yield. You can get it at a rate.

In the present invention, the reaction temperature is in the range of 150 to 400°C,
In particular, a range of 200 to 340°C is suitable.

The residence time or reaction time mainly depends on the reaction time, but is usually 1 minute to 30 hours, preferably 5 minutes to 10 hours,
Particularly preferred is a range of 10 minutes to 5 hours.

The reaction pressure may be sufficient to maintain the reaction mixture in a liquid phase, and is determined mainly by the reaction temperature and the molar ratio of raw material olefin to aldehyde.

In the reaction of the present invention, it is possible to obtain an unsaturated alcohol substantially without using a catalyst, but the use of a catalyst is not prevented in any way.

The present invention has no adverse effect even if a gas phase is generated in the reactor, and therefore, even when a reactor with a space in the upper part is used, high yield and high purity unsaturated products can be obtained. It has the characteristic that alcohol can be obtained.

This feature is particularly advantageous when stirring and mixing the reaction mixture using, for example, a stirring blade rotated by a drive device attached to the upper part of the reactor.

In other words, by pressurizing an inert gas into the space above the reactor to prevent evaporation of olefins and aldehydes, especially aldehyde, it is possible to prevent aldehyde from leaking from the seal section to the drive section, making it easier to maintain the reactor. This is extremely advantageous.

Moreover, the yield of unsaturated alcohol does not decrease at all even with the injection of such an inert gas.

Separation and recovery of the reaction products can be carried out by conventional methods without any problems.

That is, the reaction product can be subjected to the reaction again after separating and recovering unreacted olefin under increased pressure or normal pressure.

Mainly unsaturated alcohols can then be easily rectified by distillation, and the feature of the present invention in the absence of a solvent or diluent is known to be extremely advantageous in separation and purification steps.

The present invention can be carried out either batchwise or continuously.

The present invention will be explained in more detail with reference to Examples below.

The present invention is not limited in any way by these examples.

Comparative Example 1 64 g of commercially available first-class paraformaldehyde (purity 97.7%) was charged into a stainless steel 500 cc autoclave equipped with a pressure gauge, a safety valve, and an electromagnetic induction stirring device, and then the autoclave was cooled from the outside with dry ice methanol refrigerant. and add 112 g of isobutylene.

During this operation, the area around the autoclave is covered with dry air to prevent moisture in the air from condensing and entering the autoclave.

Charged isobutylene to formaldehyde molar ratio is 0.96
Met.

After raising the temperature to 230°C, the reaction was carried out for 1.5 hours, and the autoclave was cooled and unreacted substances were purged to produce a product.

When extracted and analyzed by gas chromatography,
Formation of 3-methyl-buten-3-ol-1 was observed.

Conversion rate based on formaldehyde is 98.7 mol%, 3-
The selectivity to methyl-buten-3-o1 was 25.0 mol%.

All percentages below are mol%.

Example 1 In exactly the same manner as in Comparative Example 1, 35 g of reagent-grade paraformaldehyde and 129 g of isobutylene were heated to 1.5 g at 230°C.
After reaction time, formaldehyde conversion rate was 97.0%.
The selectivity of 3-methyl-buten-3-ol-1 to reacted formaldehyde was 43.0%.

At this time, the molar ratio of isobutylene and formaldehyde is 2
．． It was 0.

Example 2 In exactly the same manner as in Comparative Example 1, 35 g of reagent-grade paraformaldehyde (purity 97.7%) and 194 g of isobutylene were prepared.
When reacted for 1.5 hours at 230°C, 3-methyl-buten-3-ol-1 was obtained with a conversion rate of 96.8% and a selectivity of 56.0% based on formaldehyde.

The isobutylene to formaldehyde ratio was 3.0.

Example 3 In exactly the same manner as in Comparative Example 1, 22 g of the same paraformaldehyde and 160 g of isobretin were reacted at 230°C for 1.5 hours, and the conversion rate of formaldehyde was 92.1%.
The selectivity of 3-methyl-buten-3-ol-1 to reacted formaldehyde was 63.0%.

The isobutylene to formaldehyde molar ratio was 4.0.

Example 4 In exactly the same manner as in Comparative Example 1, paraformaldehyde 12
3-methyl-buten-3-ol-1 was obtained with a selectivity of 83.7% relative to formaldehyde.

The formaldehyde conversion rate was 95.6%.

The isobutylene to formaldehyde ratio was 9.6.

Example 5 6 g of paraformaldehyde was prepared in exactly the same manner as in Comparative Example 1.
When 207 g of isobutylene were reacted at 230° C. for 1.5 hours, 3-methyl-buten-3-ol-1 was obtained with a selectivity of 89.5% relative to formaldehyde.

The conversion rate of formaldehyde was 98.6%.

The isobutylene to formaldehyde molar ratio was 19.

Examples 6 to 9 Paraformaldehyde 12 was prepared in exactly the same manner as in Comparative Example 1.
The results of synthesizing 3-methylbuten-3-ol-1 using the following reaction temperature and reaction time are shown below.

Both conversion rate and selectivity are based on formaldehyde.

Examples Reaction temperature Reaction time Conversion rate Selectivity (℃)
(hr) (%) (%)6 200 4.0
88.576.57 270 1.5 96.77
8.58 340 0.5 91.074.4 Example Reaction temperature Reaction time Conversion rate Selectivity (℃)
(hr) (%) (%)9 400 0.259
2.162.0 Example 10 Paraformaldehyde 12 was prepared in exactly the same manner as in Comparative Example 1.
g and 207 g of inbutylene, and the initial pressure of nitrogen was 50 hg.
/cm3.G was injected and reacted for 2.5 hours at 215 DEG C., and 3-methyl-buten-3-ol-1 was obtained with a selectivity of 75.0% relative to formaldehyde.

The conversion rate of formaldehyde was 94.0%.

Claims (1)

[Claims] 1. When reacting an olefin in which at least one hydrogen atom is bonded to at least one carbon atom adjacent to a carbon atom of a double bond with an aldehyde, the reaction is carried out without a solvent and as described below. A method for producing an unsaturated alcohol, characterized in that the process is carried out under conditions satisfying the formula (n is the number of double bonds contained in the olefin).