JPS60190729A - Production of trimethylol heptane - Google Patents

Abstract

PURPOSE:To crystallize the titled compound, by reacting n-octylaldehyde with formaldehyde in a solvent such as THF, in the presence of an alkali metal or alkaline earth metal hydroxide, distilling out the solvent, and adding an aromatic hydrocarbon to the distillation residue. CONSTITUTION:n-Octylaldehyde is made to react with formaldehyde especially at 30-50 deg.C in THF or dioxane in the presence of an alkali metal hydroxide or an alkaline earth metal hydroxide to obtain trimethylol heptane. The molar ratio of the hydroxide to n-octylaldehyde is preferably 1.0-1.5 to 1. The obtained reaction mixture is distilled to remove the tetrahydrofuran or dioxane, and the residual organic layer is added with a 6-9C aromatic hydrocarbon (e.g. benzene, xylene, etc.) to obtain the objective compound in crystal form. The weight ratio of the hydrocarbon to the organic layer is preferably 5-20.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for producing trimethylonylhebutane by methylolating n-octylaldehyde with formaldehyde.

It is already well known that when an aliphatic aldehyde represented by the general formula ROH20KO (Rs aliphatic hydrocarbon group) is reacted with formaldehyde in the presence of a base, a trimethylolalkane represented by Re (CkhOkl)s is obtained. . In particular, the production of trimethylolpropane from n-butyraldehyde is carried out on a large scale industrially, and the trimethylolpropane is used as a raw material for alkyd resins, polyurethanes, polyesters, and the like. Since both n-butyraldehyde and trimethylo-p-propane have high solubility in water, the synthesis reaction of trimethylo-μ-propane by methylolation of n-butyraldehyde must be carried out while maintaining a homogeneous system from beginning to end even in an aqueous solution. It is possible. Trimethylolhebutane obtained from n-octylaldehyde is trimethylol-μ
Although it has many superior basic physical properties compared to propane, n-
Due to the high cost of octylaldehyde and the fact that n-octylaldehyde and the product trimethylolhebutane are virtually insoluble in water, the process for its preparation may involve a number of questions. Methylolhebutane has not yet been produced on an industrial scale.

Traditionally, as a method for producing trimethylolhebutane.

Presence of surfactant [low octyl aldehyde]
f O-/l/ method (J, Atner, Che
w, 8oc, , 76°1697~9 (1954
)), the coexistence of ethanol/l/ keeps the reaction system homogeneous, and n-octylaldehyde is
Method of p conversion (Acta.

Ohem, 8cand,, 16.1062 (19
62) ) have been proposed, but in either method the yield of trimethylolhebutane was at most about 60%, which was not industrially satisfactory.

The present inventors have previously discovered an advantageous method for producing n-octylaldehyde using butadiene, water and hydrogen as starting materials (Japanese Patent Application No. 56-204997).

From this point of view, the present inventors conducted intensive research to develop an industrially advantageous method for producing trimethylylhebutane from n,-octylaldehyde, and as a result, they arrived at the present invention. That is, according to the present invention, (1) trimethylolhebutane is reacted with n-octylaldehyde and formaldehyde in the presence of an alkali metal hydroxide or an alkaline earth metal hydroxide in tetrahydrofuran or dioxane. (2) distilling the reaction mixture obtained in step (1) to remove tetrahydrofuran or dioxane; (3)
Adding an aromatic hydrocarbon having 6 to 9 carbon atoms to the organic layer obtained in step (2) and crystallizing and separating trimethylol-μ-hebutane crystals produces trimethylol-hebutane in high yield and purity. can be manufactured.

In the method of the present invention, an aqueous formaldehyde solution is usually used as formaldehyde. As the formaldehyde aqueous solution, industrially available 5-s.o.v.t.
% formaldehyde aqueous solution can be used as is. The concentration of n-octylaldehyde in the reaction solution is preferably in the range of 2 to 20% by weight based on the reaction mixture.

The amount of formaldehyde used is 371 to 6/1, especially 3.3/1 to 4 in molar ratio to n-octylaldehyde.
．． Preferably it is 2/1. If the molar ratio is less than 3/1, the amount of unreacted n-octylaldehyde remaining increases and the proportion of by-products such as di-trimethylolhebutane increases, which is not preferable. Moreover, when the molar ratio exceeds 671, the amount of by-products of various formals increases,
It is "industrially unfavorable" because the cost of recovering unreacted formaldehyde increases.

Specific examples of alkali metal hydroxides and alkaline earth metal hydroxides include lithium hydroxide, sodium hydroxide, potassium hydroxide, and hydroxide! Examples include lesium and barium hydroxide, but sodium hydroxide is particularly preferred in consideration of reaction results and cost. The amount of these alkali metal or alkaline earth metal hydroxides to be used is mo/I/L relative to n-octylaldehyde.
The range of 1.0/1 to 1.5/1 is preferable. The reaction temperature is in the range of about 5 to 100°C1, particularly preferably 3
A temperature within the range 0-50°C is chosen.

Methyl-
The p-ization reaction is carried out in tetrahydrofuran or dioxane, which can increase the reaction rate and the yield of trimethylolhebutane. Conventionally, it has been proposed to use lower alcohols as reaction solvents in the methylolation reaction of n-octylaldehyde, but according to detailed studies by the present inventors, when the reaction is carried out in these lower alcohols, It was found that various formals and hemihopers/L's were produced as by-products, and the yield of trimethylolhebutane was significantly reduced. Also hydrocarbons,
Halogenated hydrocarbons and ethers excluding tetrahydrofuran and dioxane are chemically stable under the reaction conditions, but the reaction rate, trimethyl-μ
Considering the hebutane yield, the complexity of the trimethylo-μ hebutane separation step, etc., these are unsuitable as reaction solvents.

Tetrahydrofuran or dioxane is used in an amount ranging from 0.05 to 0.9 by weight relative to the reaction mixture. If the amount of these solvents used is less than 0.05 in weight ratio to the reaction mixture, the reaction rate will slow down, and conversely, if the amount of solvent used exceeds 0.9, the cost of recovering the solvent will increase. Undesirable.

A specific method for carrying out the methylo-p conversion reaction of n-octylaldehyde is as follows: (a) Adding n-octylaldehyde, an aqueous formaldehyde solution, and an aqueous solution of an alkali metal or alkaline earth metal hydroxide to an aqueous solution containing tetrahydrofuran or dioxane. A method of reacting while simultaneously adding n-octylaldehyde and an aqueous solution of an alkali metal or alkaline earth metal hydroxide to a mixed solution consisting of an aqueous formaldehyde solution and tetrahydrofuran or dioxane. c) a method of reacting while adding an aqueous solution of an alkali metal or alkaline earth metal hydroxide to a mixed solution consisting of an aqueous formaldehyde solution, tetrahydrofuran or dioxane, and n-octylaldehyde. According to the studies conducted by the present inventors, it was found that the method (1) is the most preferable for increasing the yield of trimef-ruhebutane. In addition, in the method (1), n-octylaldehyde can also be used after being partially diluted with tetrahydrofuran or dioxane. It goes without saying that the rate of addition of these reaction reagents is determined by the reaction temperature and the cooling capacity of the reactor.

After the methylolation reaction, unreacted formaldehyde remaining in the reaction mixture is usually converted to sigmate by heat treatment in the presence of an alkali.

After the reaction mixture after the heat treatment is neutralized with formic acid or mineral acid, most or all of the solvent is recovered by distillation. The residual liquid after the solvent is distilled off contains an organic layer mainly consisting of trimethylolhebutane and an aqueous layer mainly consisting of formate. Note that precipitation of crystals can be prevented by maintaining the temperature of the residual liquid at 60° C. or higher.

The resulting organic layer may be heat-treated in the presence of an acid catalyst and water to hydrolyze various formals present in small amounts in the organic layer. This treatment can improve the yield and purity of trimethylohebutane. Acid catalysts that can be used include mineral acids such as sulfuric acid and hydrochloric acid, formic acid, and acetic acid.

Examples include organic acids such as oxalic acid and benzenesulfonic acid, and solid acids such as silica-alumina and silica-magnesia. Although the heating temperature depends on the type and concentration of the acid catalyst, a temperature within the range of 100 to 300° C. is generally selected. When heat treatment is applied to the organic layer,
If necessary, the organic layer after the heat treatment may be neutralized with an alkali.

In the method of the present invention, carbon a6 is extracted from the resulting organic layer.
Crystals of trimethylolhebutane are crystallized and separated using an aromatic hydrocarbon of ~9. According to a detailed study by the present inventors, the solubility of trimethylolhebutane in aromatic hydrocarbons is strongly dependent on temperature; it is virtually insoluble at temperatures below 50°C, while it becomes significantly insoluble at temperatures above 60°C. Indicates solubility.

Therefore, by utilizing this principle, highly purified trimethylol to butane can be efficiently obtained. The aforementioned mueta, Ohem, 8cand, , 1
6, 1062 (1962) describes the precipitation of trimethylo-hebutane as crystals from a chloroform solution, but when chloroform or esters are used, aromatic hydrocarbons No such solubility phenomenon of trimethylo-μheptane was observed,
Both the yield and purity of trimethylo-μ hebutane are low. Specific examples of aromatic R-hydrogenated compounds having a prime number of 6 to 9 include benzene, toluene, xylene, ethylbenzene, propylbenzene, trimethyflbenzene, and the like. These aromatic hydrocarbons are added to the organic PtjJ contained in the residual liquid obtained by the above-mentioned solvent distillation and/or to the organic layer separated and obtained from the residual liquid. The amount of aromatic hydrocarbon used in this case is in the range of 1 to 50, particularly preferably in the range of 5 to 20, as a weight ratio to the organic layer.

Prior to crystallizing and separating trimethylo-μ-butane from the organic layer, water and formate present in the organic layer may be removed in advance by azeotropic dehydration, filtration, sedimentation, centrifugation, etc. High purity trimethylo-p-hebutane can be obtained. The temperature 2 employed for the crystallization and separation of trimethylolhebutane is selected to be within the range of 20 to 50°C. The aromatic hydrocarbons after the crystallization and separation of trimethylol and butane are recycled and reused in the step of crystallizing and separating trimethylol and butane from the organic layer.

The method of the present invention will be specifically explained below using Examples.

Example 1 9,16 wt, % formaldehyde aqueous a369M formaldehyde (1.1287) and tetrahydrofuran 160F content II! Pour into a flask of
While stirring while keeping the internal temperature at 40°C, a tetrahydrofuran solution '17F containing n-octylaldehyde 241 (0,187 mo/I/) and 12.17 wt% sodium hydroxide aqueous solution 87F (0.1% as sodium hydroxide) were added.
265 mo/l/) were added simultaneously and continuously over a period of 2 hours. After the addition was complete, stirring was continued for an additional 20 minutes at the same temperature. Next, add 50Wt, % sodium hydroxide aqueous solution to 241%
/ was added and stirred for a further 3 hours under reflux. After the reaction mixture was adjusted to pH 7 by adding formic acid, tetrahydrofuran was distilled off under reduced pressure using an evaporator. When the residual liquid after tetrahydrofuran was distilled off was kept at 60°C, it was separated into two layers. The organic layer was taken out, and 450 d of toluene was added to this organic layer at 60°C. After water and salt were removed from the obtained toluene solution by azeotropic dehydration and filtration, the R solution was allowed to cool and left overnight at room temperature, and white crystals were precipitated. When the obtained crystals were collected and dried, 24 f/f of trimethylol to butane was obtained. The yield of trimethylolhebutane was 68% based on n-octylaldehyde.

Comparative Example 1 Trimethylohebutane was synthesized in the same manner and under the same conditions as in Example 1, except that the same weight of ethanol was used in place of tetrahydrofuran. The yield of trimethylo-p-hebutane was 18 f, and the ethyl ade μ derivative of perilla was produced as a by-product. The yield of trimethylolhebutane is 51% based on n-octylaldehyde.
%Met.

Example 2 11.27wt 6% holm/dehyde water soluble e300
g (1.127 moμ as formaldehyde) Oyohishioxane 1501 was charged into a flask with a content of 11, and while maintaining the internal temperature at 40°C, a dioxane solution containing 156 fI containing low octyl aldehyde 241 (0,187 mo/L/) was added with stirring. 6.3 wt, % Sodium hydroxide aqueous solution 178g (0.28 mo/L/ as sodium hydroxide)
) were added simultaneously and continuously over 2.5 hours. After the addition was complete, stirring was continued for an additional 20 minutes at the same temperature F.

Next, add 1te 40 wt, % sodium hydroxide aqueous solution to 2
0f/ was added and stirred for an additional 3 hours under reflux. After the reaction mixture was adjusted to pH 7 by adding formic acid, dioxane was distilled off under reduced pressure using an evaporator.

When the residual liquid after dioxane was distilled off was kept at 70°C, it was separated into two layers. The organic layer was taken out, and 4005 g of xylene was added to this organic layer at 70°C. After water and salts were removed from the obtained xylene solution by azeotropic dehydration and filtration, the r liquid was cooled to room temperature, and white crystals were precipitated. When the obtained crystals were collected and dried, 23.59 g of trimethylol hebutane was obtained. Yield of trimethylo-μhebutane based on halooctylaldehyde 6
It was 6%.

Comparative Example 2 Trimethylo-p-hebutane was synthesized in the same manner and under the same conditions as in Example 2, except that the same amount of chloroform was used in place of xylene in Example 2 and the mixing operation was carried out at 60°C. I did it. The yield of trimethylo-μ hebutane was 20.6 f.

The yield of trimethylo-p-hebutane was 58% based on n-octylaldehyde. When the same reaction was carried out using n-butyl acetate instead of chloroform, the yield of trimethylolhebutane was 17. I rarely met Of. The yield of trimethylolhebutane was 47.8% based on n-octylaldehyde.

Example 3 7,45 wt,% formaldehyde aqueous solution 381.1
/ (0.946 mol/L/ as formaldehyde) and 310 y of tetrahydrofuran were placed in a flask with a content of 11, and while maintaining the internal temperature at 40°C, a tetrahydrofuran solution containing 229 n-octylaldehyde (0,172 mol) was prepared with stirring. 48.69 and 18.9 wt 0% sodium hydroxide aqueous solution H5211 (0.246 moiv as sodium hydroxide) were simultaneously and continuously added over 1 hour and 40 minutes. After the addition was complete, stirring was continued for an additional 20 minutes at the same temperature. Next, 40 wt% aqueous sodium hydroxide solution was added at 15 feA, and stirring was continued for an additional 3 hours under reflux. After the reaction mixture was neutralized by adding formic acid, tetrahydrofuran was distilled off under reduced pressure using an evaporator. Toluene 45 is added to the residual liquid after distilling off tetrahydrofuran.
After adding 0-, the mixture was kept at 60°C, and the mixture was separated into two layers: an aqueous layer and a toluene layer. The toluene layer was removed and water and salts were removed from the toluene layer by azeotropic dehydration and filtration. A trace amount of trimethylo-p-hebutane seed crystals was added to the resulting R liquid, and when the mixture was allowed to cool to room temperature, white crystals were precipitated. When this crystal was collected and dried, 21.2p of trimethylol to butane was obtained. The yield of trimethylolhebutane is 66% based on low octyl aldehyde.
Met.

Patent applicant RiRashi Co., Ltd. Representative Patent Attorney Ken Honda

Claims (2)

[Claims] (1) Synthesizing trimethylolhebutane by reacting n-octylaldehyde and formaldehyde in the presence of an alkali metal hydroxide or alkaline earth metal hydroxide in tetrahydrofuran or dioxane, (2) The reaction mixture obtained in step (1) is subjected to distillation to remove tetrahydrofuran or dioxane, and (3)
A method for producing trimethylolhebutane, which comprises adding aromatic hydrogen ash having 6 to 9 carbon atoms to the organic layer obtained in step (2) to crystallize and separate crystals of trimethylolhebutane.