JP2990680B2 - Method for producing epoxidized tetrahydrobenzyl alcohol composition - Google Patents

Description

The present invention relates to a method for producing a novel composition containing epoxidized tetrahydrobenzyl alcohol as a main component. More specifically, the present invention relates to a method for producing a novel composition mainly comprising a mixture of four kinds of compounds.

<< Prior Art >> In recent years, epoxy compounds have become increasingly useful in a wide variety of fields, and compounds obtained by epoxidizing ethylenically unsaturated compounds such as tetrahydrobenzyl alcohol have become particularly important. Epoxidized tetrahydrobenzyl alcohol, which is a specific example, can give a polyether compound having a hydroxyl group by polymerizing the epoxy group. Further, it is a useful substance used as a diluent for epoxy resins.

<< Problems to be Solved by the Invention >> However, a composition mainly composed of a mixture of four kinds of compounds and mainly composed of epoxidized tetrahydrobenzyl alcohol as in the present invention has not been disclosed. As a result of intensive studies, the present inventors have found that an epoxidized tetrahydrobenzyl alcohol composition consisting mainly of a mixture of four types of compounds is an important composition that can be used as a polymer raw material and a diluent, The present invention has been completed.

<< Constitution of the Invention >> That is, the present invention relates to the following “general formula (II) The compound represented by the following general formula (I-1) obtained by epoxidizing a compound represented by the following formula: Containing 93 to 97% by weight of a compound represented by the following formula: 1.0 ~ 2.5wt%, 0.1 ~ 2.0wt%, 0.5 ~ 4.0 respectively
A method for producing an epoxidized tetrahydrobenzyl alcohol composition, characterized in that the composition is contained in a proportion by weight. ".

Hereinafter, the epoxidized tetrahydrobenzyl alcohol composition comprising a mixture of mainly four types of compounds obtained by the production method of the present invention will be described in detail.

First, a process for producing an epoxidized tetrahydrobenzyl alcohol (hereinafter abbreviated as ETHB) composition obtained by the production method of the present invention will be described.

The following general formula (II) as a reaction starting material Is a colorless and transparent liquid, and is used as an intermediate material for epoxy resin, ink, paint, and adhesive.

Industrially, tetrahydrobenzyl alcohol is produced by hydrogenating tetrahydrobenzaldehyde in the presence of a catalyst.

ETHB, which is the main component in the epoxidized tetrahydrobenzyl alcohol (hereinafter abbreviated as ETHB) composition obtained by the production method of the present invention, can be produced by epoxidizing tetrahydrobenzyl alcohol in the presence of an oxidizing agent.

In the production method of the present invention, it is essential to use peracetic acid.

Peracetic acid and a catalyst may be used in combination, and an alkali such as sodium carbonate or an acid such as sulfuric acid may be used as the catalyst.

The reaction is carried out continuously or batchwise. In the case of continuous reaction, a piston flow type is preferred. In the case of a batch, a semi-batch system in which peracetic acid is sequentially charged is preferable. When the reaction is carried out in batch, first, a predetermined amount of tetrahydrobenzyl alcohol is charged into a reaction vessel, and a catalyst and a stabilizer are dissolved therein as necessary, and peracetic acid is dropped therein.

Although the molar ratio of peracetic acid to tetrahydrobenzyl alcohol is theoretically one, it is practically in the range of 0.1 to 10, preferably in the range of 0.5 to 2, to produce a composition such as this invention. Preferably it is in the range of 0.8 to 1.5.

When the molar ratio of peracetic acid to tetrahydrobenzyl alcohol is greater than 10, it is preferable in terms of conversion of tetrahydrobenzyl alcohol, reduction of reaction time, and loss due to polymerization, but a side reaction due to excess peracetic acid and selectivity of peracetic acid. When the reduced and unreacted peracetic acid is recovered, it is not preferable because a large cost is required for the recovery.

Conversely, when the molar ratio of peracetic acid to tetrahydrobenzyl alcohol is 0.1 or less, the conversion and selectivity of peracetic acid are high, which is preferable in that side reactions of the product due to peracetic acid are prevented. There are drawbacks such as a large expense required for alcohol recovery.

The reaction temperature is lower than or equal to the upper limit such that the epoxidation reaction takes precedence over the decomposition reaction of peracetic acid, and specifically, is preferably 70 ° C or lower.

If the reaction temperature is low, it takes a long time to complete the reaction,
It is preferable to carry out at 0 ° C. or higher. In addition, during epoxidation, acetic acid, alcohol, and water cause a side reaction in which the epoxy group is crushed due to by-products such as peracetic acid. carry out.

The reaction pressure is generally operated under normal pressure, but it can also be carried out under elevated or low pressure. The reaction can be carried out in the absence of a solvent, but the presence of a solvent is preferred because of the effects of lowering the viscosity of the reaction crude liquid and stabilizing by diluting peracetic acid.

Examples of the solvent used include benzene, toluene, aromatic compounds such as xylene, chloroform, dimethyl chloride, carbon tetrachloride, halides such as chlorobenzene,
Ester compounds such as ethyl acetate and butyl acetate; ketone compounds such as acetone and methyl isobutyl ketone; 1,2-
An ether compound such as dimethoxyethane can be used. 0.5 for tetrahydrobenzyl alcohol
It is desirable to use up to 6 times the amount of solvent.

When the amount is less than 0.5 times, the stabilizing effect due to the dilution of peracetic acid is small, resulting in a decrease in yield. Even if the amount is more than 6 times, the effect is not changed, and a large amount of cost is required for the recovery of the solvent. In order to avoid the formation of an explosive mixture in the system, it is usual to blow nitrogen gas into the system.

The blowing position may be either directly into the liquid or into the gas phase. The blowing amount can be arbitrarily selected, but if it is too large, solvent loss will result.

The end point of the reaction may be confirmed by the concentration of residual peracetic acid or by gas chromatography. The crude reaction liquid of the epoxidation product obtained by the reaction can be purified by distilling off low-boiling components such as solvents, low-boiling substances, unreacted raw materials, and catalysts, neutralizing, treating with an adsorbent and an ion-exchange resin. . If a final product of a quality that can be used without purification is obtained, it can be omitted. In particular, if the low-boiling components are removed without neutralizing the reaction crude solution, loss increases due to ring opening of the epoxy group of ETHB with acetic acid or cyclization with the methylol group, so neutralization before removing the low-boiling components. Is preferred.

As an aqueous alkaline solution used for neutralization, for example, NaOH,
Solutions such as KOH, K ₂ CO ₃ , Na ₂ CO ₃ , NaHCO ₃ , KHCO ₃ , NH _{3 and} the like can be used, the concentration of which can be freely selected within a wide range.

It is desirable to use an aqueous solution of NaOH or an aqueous solution of Na ₂ CO ₃ from the viewpoint of liquid separation or loss.

In the neutralized water washing step, it is important to remove the residual peracetic acid in addition to neutralizing and removing acetic acid in order to stably operate the next deboiling step.

Therefore, the amount of alkali used is preferably 0.5 to 3 times, preferably 0.8 to 1.5 times the equivalent amount of the acetic acid in the reaction crude liquid, and it is economical to increase the amount more than necessary. Not.

If the equivalent ratio is reduced more than necessary, it is not advisable to use a large amount of water to remove acetic acid, and the loss of the solvent such as the solvent into the lower water increases.

After neutralization, low-boiling components are removed without washing with water, and the neutralized salt remains in the product using the bottoms as a product.

The neutralization and washing with water are preferably performed in a temperature range of 10 to 90 ° C, preferably 10 to 50 ° C. Also, it is desirable to blow nitrogen gas during neutralized water washing in order to avoid explosive mixture formation. It is preferable to use a thin-film evaporator or the like to remove low boiling components from the reaction crude liquid that has been neutralized or washed with water.

The heating temperature in the low-boiling step is 50 to 180 ° C., preferably 8 to 180 ° C.
It is good to carry out at 0 to 100 ° C. The pressure can be arbitrarily selected depending on the physical properties of the low-boiling components, but it is general to operate under reduced pressure in relation to the heating temperature.

In addition, nitrogen is usually blown into the system in order to avoid the formation of an explosive mixture in the system or to make it easy to distill low boiling components.

The blowing position can be arbitrarily selected, but is usually blown from the line from which the bottom liquid is distilled.

The amount of injection can be selected arbitrarily, but the upper limit is naturally determined from the viewpoint of the vacuum system capacity, whether the bottom liquid flows down stably, or the recovery loss when collecting the low boiling components distilled off by the condenser. Limited.

The bottom liquid obtained in this manner is 95% to 96% in terms of purity of the four compositions, but is slightly turbid and has high boiling components removed to obtain a product of higher purity. . The de-boiling step is performed in the same manner as the de-boiling step, but it is common to further increase the degree of vacuum or heating temperature to obtain a product as a distillate.

Next, the commercialized ETHB composition will be described. ETHB as a main component is represented by the following general formula (I-1) It is represented by

As a result of the study, methylol (CH ₂ O) was contained in the ETHB composition.
H) Bicyclo compounds in which oxygen attacks the epoxy carbon in the molecule and is cyclized [represented by the following general formulas (I-2) and (I-3)] Or a compound in which an epoxy group has been transferred into a molecule [represented by the following general formula (I-4)] It became clear that such was included.

One of the bicyclo compounds (I-2) is ETHB (I
It was found that the compound was easily formed by applying heat to -1).

Another bicyclo compound (I-3) is (I-
It is considered that it is difficult to be formed because the strain energy is large and the ring structure is unstable as compared with 2).

Further, in the epoxidation reaction, when the dilution ratio with ethyl acetate or the like is reduced, the proportion of the compounds (I-2) and (I-4) in the ETHB composition increases.

These compounds (I-2), (I-3) and (I-
In (4), (I-2) and (I-4) are easily generated. If the neutralization step is omitted and the low-boiling step is performed as it is, the ETHB composition contains a large amount of the bicyclo compound (I-2).

The contents of (I-1), (I-2), (I-3) and (I-4) are confirmed by using gas chromatography, ¹ H-NMR and ¹³ C-NMR. be able to. (I-1) shows ¹ H- based on two peaks of retention time of gas chromatography at 10.9 and 11.2 minutes.
3.3 and corresponding to the methylol hydrogen and hydroxyl groups in NMR
4.2p peak, plus 3.2p indicating hydrogenation of epoxide
the peak of pm, 67.0 indicating the methylol carbon of ¹³ C-NMR
ppm peak, 51.0, 53.2 ppm peak indicating epoxy carbon, cyclohexyl cyclic carbon other than epoxy carbon
It can be confirmed by peaks at 23.8, 24.0, 28.8, and 36.0 ppm.

(I-2) shows a peak at a retention time of 8.5 in gas chromatography, a peak at 3.80 ppm indicating a proton of ether methylene in ¹ H-NMR, and other peaks at 2.33 and 3.5.
From the peak of 7 ppm, it shows ether methylene of ¹³ C-NMR
It can be confirmed by a peak at 71.3 ppm and a peak at 68.2 ppm indicating methine of alcohol.

(I-3) shows a peak at a retention time of 6.5 in gas chromatography, a peak at around 3.80 ppm showing protons of ether methylene in ¹ H-NMR, a peak at 71.0 ppm showing ether methylene in ¹³ C-NMR, alcohol Can be confirmed by a peak at 68.9 ppm indicating methine.

(I-4) than the peak of retention time 8.9 Gas chromatography, 3.3 ppm showing a methylol hydrogen and hydroxyl groups of ¹ H-NMR, from two peaks of 4.2 ppm, ¹³
C-NMR peak of 67.2 ppm indicating methylol carbon, 21.0, 2 indicating cyclohexyl cyclic carbon other than epoxy carbon
It can be confirmed by peaks at 5.0, 28.0 and 32.0 ppm.

The production ratio of each component in the epoxidized tetrahydrobenzyl alcohol composition of the present invention can be controlled within the following range.

(I-1): 93 to 97% by weight (I-2): 1.0 to 2.5% by weight (I-3): 0.1 to 2.0% by weight (I-4): 0.5 to 4.0% by weight [Example 1] Water cooling 770 g of tetrahydrobenzyl alcohol and 32 parts of ethyl acetate
After adding 100 g, 1965 g of a 30% solution of peracetic acid in ethyl acetate was added to 4 g
It was dropped over time. During the dropwise addition, the temperature of the hot water flowing through the jacket was adjusted so that the reaction temperature was maintained at 30 ° C.

After the completion of the dropwise addition, the temperature of the reaction solution was kept at 30 ° C. for 4 hours to terminate the reaction.

The conversion rate based on tetrahydrobenzyl alcohol is 98%,
Epoxycyclohexene alcohol standard selectivity is 98%,
The yield was 96%.

After cooling 5935 g of the reaction crude liquid to room temperature, a 20% aqueous NaOH solution 205
After adding 7 g and stirring for 1 hour, the mixture is allowed to stand for 30 minutes to separate the layers.

After liquid separation, low boiling components of the upper layer liquid were removed. Removal of low boiling components using a glass Smith thin film evaporator, pressure 150T
At an orr at a heating temperature of 90 to 95 ° C., nitrogen gas was charged at 50 Nl / Hr from a bottom liquid distilling line. High boiling components were also removed using a glass Smith thin film evaporator at a pressure of 2 Torr and a heating temperature of 150.
The test was performed under the condition of ° C.

Gas chromatographic analysis shows a product purity of 97.
%Met.

The production ratio of each component in the epoxidized tetrahydrobenzyl alcohol composition was as follows.

(I-1): 96.5% by weight (I-2): 2.5% by weight (I-3): 0.1% by weight (I-4): 0.9% by weight [Example 2] Except that the reaction temperature was 25 ° C. The same operation as in Example 1 was performed.

 The yield was 89%.

The production ratio of each component in the epoxidized tetrahydrobenzyl alcohol composition was as follows.

(I-1): 93.5% by weight (I-2): 2.0% by weight (I-3): 2.0% by weight (I-4): 2.5% by weight [Example 3] 871 g of a 30% aqueous solution of peracetic acid in ethyl acetate Except for the above, the same operation as in Example 2 was performed. The selectivity based on epoxycyclohexene alcohol was 95%.

The production ratio of each component in the epoxidized tetrahydrobenzyl alcohol composition was as follows.

(I-1): 95.0% by weight (I-2): 1.2% by weight (I-3): 1.0% by weight (I-4): 2.8% by weight [Example 4] 349 g of a 30% aqueous solution of peracetic acid in ethyl acetate Except for the above, the same operation as in Example 2 was performed. The selectivity based on epoxycyclohexene alcohol was 100%.

The production ratio of each component in the epoxidized tetrahydrobenzyl alcohol composition was as follows.

 (I-1): 94.0% by weight (I-2): 1.5% by weight (I-3): 0.5% by weight (I-4): 4.0% by weight

[Brief description of the drawings]

FIG. 1 is a chart showing the result of analyzing the composition in [Example 1] by gas chromatography. FIG. 2 is a chart showing the results of analyzing the composition by ¹ H-NMR. FIG. 3 is a chart showing the result of analyzing the composition by ¹³ C-NMR.

Claims (1)

(57) [Claims] 1. The following general formula (II) The following general formula (I-1) obtained by epoxidizing a compound represented by Containing 93 to 97% by weight of a compound represented by the following formula: 1.0 ~ 2.5wt%, 0.1 ~ 2.0wt%, 0.5 ~ 4.0 respectively
A method for producing an epoxidized tetrahydrobenzyl alcohol composition, characterized in that the composition is contained in a proportion by weight.