JPS6118741A - Preparation of high-purity hydroxypivalic aldehyde - Google Patents

Abstract

PURPOSE:In reacting isobutylaldehyde with formaldehyde in the presence of an amine catalyst, and preparing the titled purified compound from the reaction solution, to improve yield and purity, by removing the amines from filtrates of solid-liquid separation and washing processes, using the filtrates as water to be added in crystallization or as washing water. CONSTITUTION:Isobutylaldehyde(IBA)2, formaldehyde 3, and an amine catalyst 4 are added to the reactor 1 to carry out an aldol reaction, the prepared reaction solution is fed to the low-boiling fraction cutting column 6, the low boiling fraction containing unreacted IBA is removed, and circulated through the storage tank 8 to the reactor 1. A solution at the bottom of the column 6 is sent to the crystallilizer 11, filtrates from which an amine is removed is sent from the passageway 26 in such a way that the resulting solution has 10-22wt% calculated as hydroxypivalic aldehyde(HPA) concentration, the solution is cooled and HPA is crystallized. The crystallized slurry is subjected to solid-liquid separation by the filter 13, the filtrate is circulated through the tank 28 to the reactor 1 and the column 6. The filtered cake is washed with the filtrate from which an amine is removed from the passageway 25, the filtrate is subjected to amine removal treatment by the ion exchange column 24 and circulated.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is a method for producing hydroxypivalaldehyde (hereinafter referred to as HPA) by reacting isobutyraldehyde (hereinafter referred to as IBA) and formaldehyde in the presence of an amine catalyst. Regarding.

HPA is a glycolaldehyde having a ζ-methylol group and an aldehyde group in one molecule, and is a substance useful as a raw material for 2,2-dimethylpropanediol, r-butyllactone, hydroxypivalic acid, etc.

(Prior art) HPA is produced by an aldol condensation reaction of IBA and formaldehyde in the presence of an amine catalyst, water is added to the resulting reaction product liquid, and after distilling off the low-boiling fraction, the residual liquid is A method for crystallizing, separating, and recovering HPA by cooling is disclosed in US Pat. No. 4,006,888. In this method, the mother liquor after separating and recovering HPA is IBA.
4 to 696 HPAs remaining in the mother liquor are brought into contact with I
HP A is recovered by extracting it into the BA phase and recycling it to the distillation column. However, such a method requires a large amount of I
Since BA circulates through the distillation column, it is disadvantageous in terms of energy, and HPA dissolved in the aqueous phase obtained by removing the raffinate.
, IBA, amines, etc., are disposed of outside the system without any consideration, so they are unfavorable from the viewpoint of pollution prevention and reduction of basic unit.

On the other hand, the reaction product liquid from which IBA has been distilled off is prepared in advance with added water so that the HPA concentration is in the range of 26 to 31]9, but at such a high concentration, it is cooled to 15 to 20 °C. When it is crystallized, it solidifies in the crystallizer or becomes an extremely viscous cream-like liquid and loses fluidity, which greatly impedes the subsequent separation and purification steps. As a result, not only the solid-liquid separation cannot be carried out smoothly, but also the cleaning effect particularly in the water washing step for removing residual amines is significantly lost.

If amine remains in HPA, it causes coloration, thermal decomposition, etc., and poses a major problem in terms of the quality of HPA.

(Means for Solving the Problems) The present invention eliminates these drawbacks and produces high yield and high purity H
PA is produced by performing an aldol condensation reaction of isobutyraldehyde and formaldehyde in the presence of an amine catalyst to produce hydroxypivalaldehyde, adding water to the resulting reaction product liquid, and cooling it to crystallize hydroxypivalaldehyde. In the method of solid-liquid separation and further washing with water to obtain high-purity hydroxypivalaldehyde, the f-liquid or washing liquid obtained in the solid-liquid separation and washing step is deamined and then crystallized. This is a method for producing high-purity hydroxypivalaldehyde by using it as addition water and/or washing water.

The formaldehyde used in the present invention may be an aqueous formaldehyde solution (formalin) or mohalaform, but the aldol condensation reaction of IBA and formaldehyde using an amine catalyst is extremely susceptible to the water concentration in the reaction system. If the formalin is diluted, the reaction rate slows down and a constant yield cannot be obtained, so it is preferable that the concentration of formalin be as high as possible.

In particular, in the present invention, a part of the crystallized P solution in the subsequent process is recycled to the reaction system for the purpose of recovering HPA and amines, so if dilute formalin is used as a raw material,
The amount of P liquid circulated is limited, which results in a corresponding decrease in the amount of amine recovered.

Therefore, it is preferable that the raw material formalin has a concentration of 67% by weight or more and does not contain methanol or contains as little methanol as possible.

The aldol condensation reaction of IBA and formaldehyde in the present invention may be carried out either batchwise or continuously. Further, it is preferable to carry out the method under normal pressure with no air exclusion or in a nitrogen stream.

The molar equivalent of IBA to formaldehyde is 0.
It is carried out within the range of 95 to 1.30, but preferably 0°98
~1.10.

In the case of a batch reaction, the reaction is heterogeneous for several minutes from the start of the reaction, but changes to a homogeneous reaction as HPA production increases.

The reaction temperature is 40-98°C under normal pressure, preferably 80-98°C.
The temperature is 95°C.

In the case of a batch reaction, the reflux point of IBA is 6 under normal pressure.
Temporarily stops at 2-65°C, but increases in HPA production (IB
consumption of A) gradually rises to 94-95℃.
reach.

In the case of continuous reaction, the reaction is homogeneous and the reaction temperature is 9
The temperature will be 4-95°C.

The present invention uses amines as catalysts. There are no particular restrictions on the type of amine catalyst, but tertiary amines are generally preferred.

For example, trimethylamine, triethylamine, tripropylamine, triisopropylamine, tributylamine, triisobutylamine, N-methylpiperidine,
N-ethylpiperidine, N-ethylpiperidine, N-methylmorpholine, N-ethylmorpholine, N-methylpyrrolidine, N-ethylpyridine, and the like are effective. The amount of the amine catalyst added is 0.01 to 0 in molar equivalent to IBA.
．． 1, preferably 0.02 to 0.05. A low-boiling fraction containing unreacted IBA as a main component is distilled off from the thus obtained first HPA reaction product liquid according to a conventional method.

The entire amount of the distilled off low-boiling fraction is recycled to the reaction system for use.

Next, HPA is crystallized from the reaction product liquid after distilling off the low-boiling fraction, but the reaction product liquid is diluted with water in order to smoothly perform crystallization and subsequent solid-liquid separation. In the present invention, in particular, the f liquid or washing liquid obtained in the solid-liquid separation and washing steps is diluted by adding water obtained by deamine treatment. The dilution is preferably carried out so that the HPA concentration is 10 to 22% by weight.

If crystallization occurs when the HPA concentration is too high, it will solidify in a form that incorporates water. In this state, fluidity is completely lost, making it difficult to handle. Furthermore, in this state, it becomes extremely difficult to remove amines and the like incorporated therein.

To adjust the HPA concentration during crystallization, the P liquid produced during solid-liquid separation in the subsequent process is circulated to the reaction system, circulated to the low-boiling fraction cut column, and deamined in the ion exchange resin column in the subsequent process. The crystallization temperature is 5 to 40 degrees Celsius, preferably 15 to 35 degrees Celsius, which is carried out by adjusting the ratio of the three circulations of the applied F liquid to the crystallizer.
It is.

The crystals obtained by the crystallization operation are subjected to solid-liquid separation (filtration) and washing to remove residual amines contained in the filter cake.

Liquid f is produced during solid-liquid separation before washing (this is called liquid I).

) and the f liquid (this will be referred to as f liquid ①) produced during cleaning are preferably treated separately.

That is, since liquid I contains amine at a high concentration, a part of it is circulated as it is to the aldol condensation reaction system, and a part is circulated to the low boiling fraction cut column to remove the amine. Trying to recover.

On the other hand, P liquid (2) passes through an ion exchange resin tower to adsorb and remove remaining amines.

Part of the P liquid that has been deamined with an ion exchange resin is used as added water during product analysis, and the remaining part is used as washing water.

A cation exchange resin is used as the ion exchange resin for deamination.

There are no restrictions on the type of cation exchange resin, and known examples include styrene, phenol, or methacrylic resins with cation exchange groups such as sulfone, carboxyl, phenolic hydroxyl, phosphonic, or arsone groups. It has the following.

Among these cation exchange resins, those having sulfone groups in the styrene resin matrix are preferably used because of their high deamination rate and high adsorption amount.

Ion exchange resins that have lost their exchange ability due to deamine treatment can be reused by regenerating them using a conventional method, for example, with an aqueous solution of hydrochloric acid or sulfuric acid.

The filter cake obtained by solid-liquid separation and washing is then dried.

Although there are no particular restrictions on the drying method, it is preferable to carry out the drying at a temperature of 55° C. or lower.

That is, at temperatures above 55'C, in the early stage of drying when the moisture content is high, HPA melts, and as it dries, HPA dissipates greatly, and in the latter stage, neopentyl glycol/hydroxypivalic acid mono, which is a trimerized compound of HPA, melts. May result in ester formation.

Next, the present invention will be explained in more detail with reference to the attached drawings. Figure 1 shows an example of the process for carrying out the present invention.
and conduct the aldol condensation reaction.

The reaction product liquid is supplied to a low-boiling fraction cut tower 6 from a route 5,
Here, low-boiling fractions containing unreacted IBA are removed and recovered. The recovered low-boiling fraction is temporarily retained in a retaining tank 8 via a route 7, and is sequentially circulated and supplied to the reactor 1 via a route 9.

On the other hand, the bottom liquid of the low fraction cut tower 6 is supplied to the crystallizer 11 through a route 10.

At this point, the deamined R liquid is supplied through the route 26 so that the HPA concentration becomes 10 to 22% by weight, and HPA is crystallized. The HPA crystallization slurry liquid is supplied to an f-filter 13 through a path 12, where it is separated into solid and liquid.

A part of the f liquid extracted at this time is from the primary r
The liquid is temporarily stored in a liquid tank 28 and sequentially supplied to the reactor 1 through a route 29.

Further, the remainder is supplied to the low-boiling fraction cut column 6 through the route 30.

On the other hand, the HPA that has become a filter cake is washed with the deamined P solution from route 25, and then from route 14 to the dryer 1.
5. In the dryer, hot air of 55° C. or lower is sent from path 19 to dry the material. Moisture generated by drying is discharged from the yarn through the path 20.

The purified HPA dried in this way is sent to a filling machine 17 through a path 16 and becomes a product HPA through a path 18.

On the other hand, the R liquid discharged during cleaning is routed to the F liquid tank 2.
2, supplied to the ion exchange resin tower 24 via route 23;
The amine remaining in the P solution is adsorbed and removed. A part of this deaminated P liquid is again supplied to the crystallizer 11 through the route 26 and used as additive water, and the remaining part is supplied to the filter 13 through the route 25 to be used as washing water during filtration. Use as.

(Effect of the invention) According to the present invention, the filter obtained in the solid-liquid separation step and the washing step can be used as dilution water for diluting the reaction product liquid in the crystallizer and/or as a washing liquid for the cake separated in the solid-liquid separator. Because the liquid and cleaning liquid are deamined,
HPA is not dissolved and lost in f-liquid and cleaning solution,
In addition, since dissolved active ingredients such as IBA and amines are also recovered, highly purified HPA can be produced at a high yield, which is extremely advantageous not only from the viewpoint of improving the unit consumption but also from the viewpoint of pollution prevention.

(Example) Next, the present invention will be described in more detail by showing examples.

In the examples, "%" and "parts" mean "% by weight" and "parts by weight", respectively.

Further, the numbers indicating the devices used in Example 5 are as shown in FIG.

Example 1 59.5 parts of 1BA and 65.7 parts of 37% formalin were mixed [stirred at 45°C in a nitrogen stream;
5 parts of triethylamine (TEA) were added. The temperature of the reaction mixture rises to 62 to 64° C. in 5 to 7 minutes, and the IBA refluxes violently, but the reflux gradually becomes gentler. The reaction solution temperature reached 90C after 20 minutes. The reaction was further carried out for 30 minutes at 92 to 94°C to obtain 5 parts of a reaction product solution of 128°C. The composition of this reaction product liquid was analyzed using gas chromatography, and the result was that it had a composition similar to that of the method.

HPA63.1096, IBAo, 86%, TEA2.
56%, methanol j, 5596 and water 31.18% From this reaction product liquid, temperature 60~65℃, pressure 400~4
12.1 parts of low-boiling fractions such as unreacted IBA were distilled off under 10 dragons of Hg.

The distillate amount is 9.4% of the reaction product amount, and its composition is H
PA2.6496, IBA9.1796, TEA3.3
96, methanol 15.796 and water 7S 9.17%
Met.゛The HPII degree of the reaction product liquid after distilling off the low boiling fraction is 16.5.
373.3 parts of water was added so that the temperature was 96°C, and the mixture was cooled to 35°C.

Next, the mixture was stored under stirring for 1 hour, and then solid-liquid separation was performed using a top-discharge centrifuge. At this time, 598.1 parts of F liquid was discharged to obtain 91.6 parts of cake HPA.

As a result of analyzing the composition of f-liquid, HPA6.5%, TEA
o, 6%, water 92.796, others 0°296.

The cake HPA was washed with 230 parts of fresh water.

At this time, 246 parts of P solution ■ is discharged, and the cake HPA
75.6 parts were obtained.

As a result of analyzing the composition of R liquid ■, HPA 3.5%, TEA
o, 8%, water 95.696, the pond 0°196.

As a result of analyzing the washed cake HP A, HPA61
．． 4%, water 38.696.

This cake HPA was dried in a tray dryer under a 50" C1 vacuum to obtain 46.4 parts of product HPA.

This was the product layer.

On the other hand, the f-liquid (product name: Abarai) IR-
Deamination was performed using 120B (cation exchange resin).

Next, 398.1 parts of liquid I was divided into two parts, of which 21.
5 parts and also 12.1 parts of the low boiling fraction are recycled to the reactor, to which are added 58.4 parts of IBA and 40.5 parts of 60% formalin.
TE
2.77 parts of A was added and the reaction was carried out in the same manner as above.

The remainder of P liquid I was added to this reaction product liquid, and the low boiling fraction was distilled off.

After distilling off the low boiling fraction, the reaction product liquid was crystallized and separated into solid and liquid in the same manner as above.

Furthermore, this cake HPA was washed with a P solution obtained by previously deaminating it with an ion exchange resin.

It was dried in the same manner as above to obtain 78.5 parts of product HPA. This was designated as product ■.

As shown in Table 1, this product was as high quality as the other products.

Table 1 Example 2 1,240 parts of IBA and 4096 formalin i, 32
8 parts were mixed and stirred at 45°C in a nitrogen stream, and 67
of TEA was added, and the aldol condensation reaction and low boiling fraction were cut in the same manner as in Example 1 to obtain 2,371 parts of reaction product liquid and 264 parts of low boiling fraction.

The HPA concentration in the reaction product liquid after distilling off this low-boiling fraction was 21.
．． 1.6,500 parts of 3.5% HPA to make 6%
Aqueous solution was added and cooled to 40''C.

Next, the mixture was stored under stirring for 1 hour, and then solid-liquid separation was performed using a cylindrical (Sharpless type) centrifuge.

At this time, 5,895.2 parts of P liquid I was discharged to obtain 2,775.8 parts of cake HPA.

Next, add 5,400 parts of this cake HPA to 6°5% HPA.
Washed with aqueous solution.

At this time, 5,525.8 parts of liquid f was discharged to obtain 2,650.0 parts of cake HPA.

This cake HPA was dried for 40 minutes using a batch-type box-type aerated dryer.
It was dried under ventilation at ~45°C to obtain 1,585 parts of product HPA. This was designated as Product I.

Next, 5,895.2 parts of the F liquid layer was divided into two parts, of which 1,
769 parts and 264 parts of the previous low-boiling fraction were circulated to the reactor, 1.215 parts of IBA and 1.205 parts of 40% formalin were mixed therewith, stirred at 45°C in a nitrogen stream, and TEA 48 parts were added and the reaction was carried out in the same manner as above.

The remainder of P liquid I was added to this reaction product liquid, and the low boiling fraction was distilled off.

The reaction product liquid after distilling off the low boiling fraction was crystallized and separated in the same manner as above.

Furthermore, the cake HPA was washed with the P solution obtained by deaminating it using the ion exchange resin.

It was dried in the same manner as above to obtain 605 parts of product HPA'l. This was designated as product ■.

Table 2 shows the quality test results for Product I and the product layer.

Table 2 Example 6 The same method as in Example 2 was used except that the catalyst was N-methylpiperidine and the degree of HPAa during crystallization was adjusted to 18.5%. Product I was obtained.

Table 3 Example 4 The catalyst was prepared using tripropylamine and the HPA concentration during crystallization was adjusted to 15.0%.
The process was repeated 0 times to produce 15,908 parts of HPA.

The quality analysis of the composites of the 1st to 10th products revealed that they were of high quality as shown in Table 4.

Table 4 Example 5 IBA 666.2 parts/hour from route 2, 40% formalin 381.4 parts/hour from route 3, triethylamine 16.7 parts/hour from route 4, low boiling fraction 140
．． 0 parts/hour from route 9 and P solution I, 639.5 parts/hour
time was supplied to reactor 1 through route 29, respectively. In reactor 1, an aldol condensation reaction was carried out at 92 to 94° C. under normal pressure in a nitrogen stream.

Reaction product liquid 1543. extracted from the bottom of reactor 1.
8 parts/hour is from route 5, and P liquid 1.1433.5 parts/hour.
The water was supplied to the low-boiling fraction cut column 6 through a route 30.

140.0 parts/hour of the low-boiling fraction distilled off in the low-boiling fraction cut tower 6 passed through a retaining tank 8 via a route 7, and was returned to the reactor 3 via a route 9 to be reused in the aldol condensation reaction. .

2697.2 parts/hour of the reaction product liquid extracted from the bottom of the low-boiling fraction cut tower 6 was supplied to the crystallizer 11 via route 1o. On the other hand, this crystallizer 11 contains the deamined P liquid It.
91.7 parts/hour is supplied from route 26, HP, l
Once adjusted to 21°6%.

The temperature of the crystallizer 11 was kept constant at 30° C. to continuously crystallize HPA.

HPA slurry liquid extracted from the bottom of crystallizer 11
2789.0 parts/hour was supplied to centrifuge 13 via path 12.

The centrifugal separator 13 of this tamp is divided into a solid-liquid separation section and a washing section.
parts/hour were supplied to the washing section through path 24 to wash the cake HPA.

Washed cake HPA 720.0 parts/hour is route 1
4 was supplied to the vacuum dryer.

502.0 parts/hour of dried HPA was supplied to a filling machine 17 through a route 16, sequentially packed into bags, and extracted as a product through a route 18.

Thus, HPA was produced continuously for 14 days.

The i(PA) of the obtained product was of high quality as shown in Table 3.

Table 6

[Brief explanation of the drawing]

FIG. 1 is an example of a process diagram for continuously producing HPA by the method of the present invention. In the drawing, 1 is a reactor, 6 is a low-boiling fraction cut column, 8 is a low-boiling fraction retention tank, 11 is a crystallizer, 13 is a solid-liquid separator, and 22
and 28 is an r liquid holding tank, 24 is an ion exchange resin tower, 1
5 is a dryer, and 17 is a filling machine. Permit applicant Mitsubishi Gas Chemical Co., Ltd. Representative Kazuyoshi Nagano

Claims (1)

[Claims] Produce hydroxypivalaldehyde by subjecting isobutyraldehyde and formaldehyde to an aldol condensation reaction in the presence of an amine catalyst, adding water to the resulting reaction product liquid, cooling it to crystallize hydroxypivalaldehyde, and separating it into solid and liquid.
In the method of obtaining high-purity hydroxypivalaldehyde by further washing with water, the filtrate and washing liquid obtained in the solid-liquid separation and washing steps are deamined, and then the water added during crystallization and/or washed A method for producing high-purity hydroxypivalaldehyde, which is characterized in that it is used as water.