JP4883976B2 - Method for producing high-purity dioxane glycol - Google Patents

Description

  The present invention produces 5-ethyl-2- (1,1-dimethyl-2-hydroxyethyl) -5-hydroxymethyl-1,3-dioxane (hereinafter referred to as dioxane glycol, DOG) having high trans form purity. On how to do.

ＤＯＧは例えばヒドロキシピバルアルデヒド（以下、ＨＰＡと称する）とトリメチロールプロパン（以下、ＴＭＰと称する）とを酸触媒下、アセタール化反応させて合成され、反応中に析出したＤＯＧの結晶をろ過、洗浄、乾燥の工程を経ることにより得られることが開示されている（特許文献１参照）。
特公昭６２−５９１０４号公報 5-ethyl-2- (1,1-dimethyl-2-hydroxyethyl) -5-hydroxymethyl-1,3-dioxane has the following chemical structure.

DOG is synthesized, for example, by acetalization reaction of hydroxypivalaldehyde (hereinafter referred to as HPA) and trimethylolpropane (hereinafter referred to as TMP) under an acid catalyst, and the DOG crystals precipitated during the reaction are filtered. It is disclosed that it can be obtained through a washing and drying process (see Patent Document 1).
Japanese Examined Patent Publication No. 62-59104

Due to its structure, DOG has two types of isomers, trans and cis, as follows. When DOG itself or a derivative thereof is used as an industrial raw material, it is not preferred that both the trans form and the cis form are mixed because the physical properties of the target compound are deteriorated, and the purity of the trans form is high (hereinafter referred to as “trans form”). (Referred to as high purity).

  However, in the previously disclosed production method, there is no description regarding the isomeric purity of DOG. Thus, as a result of intensive studies by the present inventors, it has been clarified that DOG obtained by the previously disclosed production method is mainly in a trans form but has a low trans form purity. Among the DOGs obtained in the examples of Patent Document 1, the one having the highest melting point is 121.5 ° C., but the DOG obtained by the method of Patent Document 1 was further recycled using acetone as a solvent. The melting point of a DOG pure product obtained by crystal purification and having a trans purity of 99% or higher was 125 ° C. or higher.

  As described above, it is possible to further purify the DOG obtained by the previously disclosed method by recrystallization or the like, but not only the necessary secondary materials increase, but also DOG This greatly increases the number of manufacturing steps, which is industrially disadvantageous.

  An object of the present invention is to solve the problems associated with the prior art as described above, and to provide a method for producing a high purity DOG having a high trans body purity.

As a result of intensive studies in order to obtain a high purity DOG having a high trans isomer purity as described above without providing a purification step, the present inventors have added either one of HPA solution and TMP or TMP solution to the other. Thus, the present inventors have found that a high purity DOG having a high trans isomer purity can be easily produced by carrying out the reaction while reaching the present invention.
That is, the present invention relates to a high-purity DOG production method described in the following (1) to (6).
(1) A method for producing DOG by reacting TMP and HPA in the presence of an acid catalyst, wherein the following conditions (a) to (c) are satisfied.
(A) The reaction is carried out while adding either the HPA solution or TMP or TMP solution to the other. (B) The time for adding either the HPA solution or TMP or TMP solution to the other is 0.5 hour or more. (C) The theoretical amount of DOG that can be synthesized from TMP and HPA is in the range of 3 to 35% by weight with respect to the total amount of acid catalyst, HPA solution, and TMP or TMP solution. (2) HPA solution The method for producing high-purity DOG according to (1), wherein the acid catalyst is added to a mixed TMP solution.
(3) The method for producing high-purity DOG according to (1), wherein the HPA solution and the acid catalyst are simultaneously added to the TMP solution.
(4) The method for producing high-purity DOG according to (1), wherein a TMP or a TMP solution and an acid catalyst are simultaneously added to the HPA solution.
(5) The method for producing high-purity DOG according to (1), wherein TMP or a TMP solution mixed with an acid catalyst is added to the HPA solution.
(6) The method for producing high-purity DOG according to any one of (1) to (5), wherein the time for adding any one of the HPA solution, TMP or TMP solution to the other is in the range of 0.5 to 24 hours. .

  Since the present invention provides a high purity DOG having a trans form purity sufficient to be used as various industrial raw materials and can be usefully used as a raw material for polymer materials and various chemical products, the industrial significance of the present invention is great. .

  The present invention is a method for producing DOG by reacting TMP and HPA in the presence of an acid catalyst, characterized by reacting while adding either an HPA solution or TMP or TMP solution to the other. This is a method for producing high-purity DOG.

  In the present invention, high-purity DOG is produced by reacting TMP with HPA in the presence of an acid catalyst. The TMP used in the reaction may be a commercially available product, or may be purified by further distilling or crystallizing a commercially available product. TMP is used in the reaction as it is or as a TMP solution using water, an organic solvent, or a mixed solvent of an organic solvent and water. It is preferably used in an aqueous solution. Examples of the organic solvent include alcohols and ethers. When TMP is used as a solution, the TMP concentration in the TMP solution is preferably 10 to 99% by weight.

  On the other hand, the HPA used for the reaction may be the one obtained by the reaction of isobutyraldehyde and formaldehyde (formalin) as it is, or may be purified by a known method such as crystallization with water. good. Here, when purified, the concentration of formaldehyde contained in HPA is preferably 2.2% by weight or less. More preferably, it is 1.0 weight% or less. If the formaldehyde concentration is higher than this, the amount of cis-form produced increases. HPA is used in the reaction as an HPA solution using water, an organic solvent, or a mixed solvent of an organic solvent and water. It is preferably used in an aqueous solution. Examples of the organic solvent include alcohols and ethers. The HPA concentration in the HPA solution is preferably 10 to 99% by weight.

The reaction solvent is preferably water, but an organic solvent or a mixed solvent of an organic solvent and water may be used. The molar ratio of HPA to TMP (HPA / TMP) is 0.7 to 2.5, preferably 0.9 to 1.5, and more preferably 1 to 1.3. If it is larger than this, HPA that is not involved in the reaction increases in the reaction solution, so that side reactions such as HPA decomposition and HPA dimerization tend to proceed, not only the deterioration of the HPA basic unit, DOG product purity also deteriorates. On the other hand, when it is smaller than this, since DOG dissolves well in a solution containing a large amount of TMP, most of the produced DOG dissolves in the mother liquor, and the yield becomes very low.

  The acid catalyst used in the reaction is not particularly limited, but in general, a mineral acid such as hydrochloric acid, sulfuric acid, phosphoric acid and nitric acid, or an organic acid such as benzenesulfonic acid, toluenesulfonic acid and methanesulfonic acid is used. . At this time, the amount of the acid catalyst required varies depending on the type of the acid catalyst, and the pH value of the reaction solution during the reaction is 0.1 to 3.0, preferably 0.2 to 2.5, more preferably 0.8. It should be between 3 and 2.0. When the pH value is less than 0.1, there is no influence on the yield of DOG and the purity of trans form obtained, but the risk of device corrosion increases. Moreover, when pH value is larger than 3.0, the reactivity will become very low and the yield of DOG will fall.

In the present invention, the reaction is carried out while adding either the HPA solution or the TMP or TMP solution to the other. In particular,
(1) Continuously (less than 5 seconds when supply of the solution is interrupted during the reaction) or intermittently in the TMP solution mixed with the acid catalyst in which the HPA solution has been preliminarily set at the same temperature as the reaction temperature (described later) (The time during which the supply of the solution is interrupted during the reaction is 5 seconds or longer)
(2) A method in which an HPA solution and an acid catalyst are continuously or intermittently dropped simultaneously into a TMP solution that has been set to a temperature approximately equal to the reaction temperature.
(3) A method in which a TMP or a TMP solution and an acid catalyst are continuously or intermittently dripped simultaneously into an HPA solution that has been set to a temperature approximately equal to the reaction temperature.
(4) The method of adding the TMP mixed with the acid catalyst or the TMP solution to the HPA solution continuously or intermittently may be used.

  The reaction temperature is preferably 40-60 ° C, more preferably 50-60 ° C. When the reaction temperature is less than 40 ° C., the reaction time becomes long, which is industrially disadvantageous. Moreover, when reaction temperature exceeds 60 degreeC, the trans-isomer purity of DOG obtained will fall. Although there is no restriction | limiting in particular in the reaction pressure, it is practical to carry out under a normal pressure industrially.

  As a reaction method, raw materials other than the raw material to be added to the reactor are charged, the raw material to be added after heating to a predetermined temperature, or a solution containing the raw material to be added is 0.5 to 24 hours, preferably 1 to 12 hours. More preferably, it is added over 1.5 to 6 hours. If the addition is performed in a shorter time than this, the purity of trans form is lowered. In addition, when the time required for addition is longer than this, although no particular inconvenience is seen in the trans purity of the DOG, the yield, etc., the time required for the reaction is too long, which is not preferable from an industrial standpoint.

  In the present invention, the maximum amount (theoretical amount) of DOG that can be synthesized from TMP and HPA is 3 to 3 with respect to the total amount of the acid catalyst, hydroxypivalaldehyde solution, and trimethylolpropane solution. It is charged in a range of 35% by weight, preferably 10 to 30% by weight, more preferably 13 to 25% by weight (this ratio (% by weight) is X). X corresponds to the DOG concentration in the reaction product solution in which the reaction has progressed 100%, and DOG is almost precipitated as crystals, which is at the same level as the crystal concentration in the reaction product solution at the end of the reaction. . In a dilute system where X is less than 3% by weight, the amount of DOG produced per reaction is low, which is industrially disadvantageous. On the other hand, if it exceeds 35% by weight, the crystal concentration in the reaction product solution is too high to be sufficiently stirred, and the trans purity of DOG is greatly deteriorated. Moreover, it becomes difficult to transfer the reaction product liquid, which is not preferable for industrial operation.

  After completion of the dropwise addition, aging is performed at a temperature similar to the reaction temperature over 0.5 to 12 hours, preferably 1 to 8 hours, more preferably 1.5 to 6 hours. When the ripening reaction is completed in a short time, the DOG yield decreases because the reaction progress is insufficient. In addition, when the time required for addition is longer than this, although no particular inconvenience is seen in the trans purity of the DOG, the yield, etc., the time required for the reaction is too long, which is not preferable from an industrial standpoint. After completion of the reaction, neutralization may be performed so that the pH of the reaction product solution is 4 or more.

  The reaction product solution obtained by the above reaction deposits high-purity DOG, which is the target product, from which the DOG cake is separated by filtration or centrifugation. After separating the DOG cake from the mother liquor, it is common to perform crystal washing with the solvent used in the reaction. Finally, the obtained DOG cake is dried to obtain a product.

Next, the present invention will be described more specifically. However, the present invention is not limited to this.
In addition, the gas chromatography (henceforth GC) analysis conditions of a reaction product liquid and product DOG are shown below.
<GC Analysis Conditions for HPA Synthesis Reaction Solution>
A capillary column (Agilent Technologies DB-1 equivalent) was used to prepare an acetone solution for analysis.
<GC condition of trans body purity of product DOG>
A capillary column (Agilent Technologies DB-1 equivalent) was used to prepare an acetone solution for analysis.

<Example 1>
While stirring 601 parts by weight of isobutyraldehyde (hereinafter referred to as IBD) and 657 parts by weight of 37% by weight formalin under a nitrogen stream at 40 ° C., 33 parts by weight of triethylamine (hereinafter referred to as TEA) was added over 5 minutes. It was. At the end of the TEA addition, the reaction temperature reached 65 ° C. From here, the temperature of the reaction solution was gradually increased to 90 ° C. after 30 minutes. The reaction was continued at 90 ° C. for 5 minutes, and then cooled to 60 ° C. by external cooling to stop the reaction. Subsequently, when low boiling fractions such as unreacted IBD, TEA, and methanol were distilled off at 60 to 70 ° C. and a pressure of 53 kPa, 1191 parts by weight of an HPA synthesis reaction liquid (hereinafter referred to as crude HPA) was obtained. It was. As a result of analyzing the composition of this crude HPA by GC, HPA 62.4% by weight, IBD 0.3% by weight, TEA 0.3% by weight, neopentyl glycol 0.6% by weight, hydroxypivalate neopentyl glycol monoester 2.0% by weight %, And 28.5% by weight of water.
916 parts of TMP was dissolved in 3825 parts by weight of water to make a TMP solution, 100 parts by weight of concentrated hydrochloric acid was added, and the mixed solution was heated to 60 ° C. Next, 1191 parts of the crude HPA was added dropwise to the mixed solution over 3 hours while maintaining the reaction temperature at 60 ° C. After completion of dropping, the mixture was aged for 2 hours at 60 ° C. After completion of aging, the mixture was cooled to 40 ° C. and neutralized with a 25% aqueous sodium hydroxide solution to pH 7. The reaction product solution was centrifuged, washed with 1520 parts by weight of water, and then sufficiently dehydrated to obtain 1580 parts by weight of a wet DOG cake. Thereafter, the wet DOG cake was dried under reduced pressure to obtain 1267 parts by weight of a DOG product. Said X was 21 weight% and the yield of DOG with respect to TMP charged was 85 mol%. The melting point of the obtained DOG was 125.5 ° C., and as a result of analysis using GC, the trans isomer purity of this crystal was 99.5%.

<Example 2>
1191 parts by weight of crude HPA and 100 parts by weight of concentrated hydrochloric acid obtained in the same manner as in Example 1 were added to a mixed solution of 916 parts by weight of TMP and 3825 parts by weight of water that had been heated to 60 ° C. over 3 hours each. did. After completion of dropping, the mixture was aged for 2 hours at 60 ° C., and then subjected to the same post-treatment as in Example 1 to obtain 1240 parts by weight of a DOG product. Said X was 20 weight% and the yield of DOG with respect to TMP charged was 84 mol%. The melting point of the obtained DOG was 125.3 ° C., and as a result of analysis using GC, the trans form purity of this crystal was 99.4%.

<Example 3>
A mixed solution of 916 parts by weight of TMP and 500 parts by weight of water, and 100 parts by weight of concentrated hydrochloric acid, each for 3 hours, were heated to 60 ° C. in advance for 1191 parts by weight of crude HPA obtained in the same manner as in Example 1. It added to the mixed solution of 3325 weight part of water. After completion of dropping, the mixture was aged for 2 hours at 60 ° C., and then subjected to the same post-treatment as in Example 1 to obtain 1255 parts by weight of a DOG product. Said X was 21 weight% and the yield of DOG with respect to TMP charged was 85 mol%. The melting point of the obtained DOG was 125.2 ° C., and analysis using GC revealed that the crystal had a trans purity of 99.3%.

<Example 4>
To a mixed solution of 1191 parts by weight of crude HPA and 3325 parts by weight of water obtained in the same manner as in Example 1, in which 916 parts by weight of TMP, 500 parts by weight of water, and 100 parts by weight of concentrated hydrochloric acid were heated to 60 ° C. in advance. Added over 3 hours. After completion of dropping, the mixture was aged for 2 hours at 60 ° C., and then subjected to the same post-treatment as in Example 1 to obtain 1260 parts by weight of a DOG product. Said X was 21 weight% and the yield of DOG with respect to TMP charged was 85 mol%. The melting point of the obtained DOG was 125.4 ° C., and as a result of analysis using GC, the trans form purity of this crystal was 99.5%.

<Comparative Example 1>
A reaction was carried out in the same manner as in Example 1 except that crude HPA and TMP were charged simultaneously, and post-treatment was carried out in the same manner as in Example 1. As a result, 1200 parts by weight of DOG was obtained. Said X was 20 weight% and the yield of DOG with respect to TMP charged was 81 mol%. However, the melting point of DOG obtained was 121.5 ° C., and as a result of analysis using GC, the trans purity of this crystal was 90%.

<Comparative example 2>
The reaction was carried out in the same manner as in Example 1 except that the addition of crude HPA was performed over 0.3 hours, and the post-treatment was also carried out in the same manner as in Example 1. As a result, 1220 parts by weight of DOG was obtained. Said X was 20 weight% and the yield of DOG with respect to TMP charged was 82 mol%. However, the melting point of DOG obtained was 122.0 ° C., and as a result of analysis using GC, the trans purity of this crystal was 92%.

<Comparative Example 3>
The reaction was performed in the same manner as in Example 1 except that 961 parts by weight were used as water for dissolving TMP, and the post-treatment was also performed in the same manner as in Example 1. As a result, 1280 parts by weight of DOG was obtained. Said X was 40 weight% and the yield of DOG with respect to TMP charged was 85 mol%. However, the melting point of DOG obtained was 120.5 ° C., and as a result of analysis using GC, the trans purity of this crystal was 85%.

  High-purity DOG is a polyhydric alcohol having a cyclic acetal in the molecule, and as an intermediate or monomer of a polymer material such as poly (meth) acrylate, polycarbonate, polyester, polyurethane, polyether polyol, epoxy resin, etc. Is a compound useful as a raw material for photocurable resins, adhesives, photocurable inks, plasticizers, resin stabilizers, lubricating oils, paints and the like.

Claims (6)

5-methyl-2- (1,1-dimethyl-2-hydroxyethyl) -5-hydroxymethyl-1,3-dioxane is produced by reacting trimethylolpropane with hydroxypivalaldehyde in the presence of an acid catalyst. High-purity 5-ethyl-2- (1,1-dimethyl-2-hydroxyethyl) -5-hydroxymethyl-1 which satisfies the following conditions (a) to (c): , 3-Dioxane production method.
(A) A reaction is carried out while adding either a hydroxypivalaldehyde solution or trimethylolpropane or a trimethylolpropane solution to the other (b) either a hydroxypivalaldehyde solution or a trimethylolpropane or a trimethylolpropane solution (C) 5-ethyl-2- (1,1-dimethyl-2-hydroxyethyl) -5 that can be synthesized from trimethylolpropane and hydroxypivalaldehyde -The theoretical amount of hydroxymethyl-1,3-dioxane is charged in a range of 13 to 30% by weight with respect to the total amount of the acid catalyst, hydroxypivalaldehyde solution and trimethylolpropane or trimethylolpropane solution.   The high purity 5-ethyl-2- (1,1-dimethyl-2-hydroxyethyl) -5-hydroxymethyl according to claim 1, wherein the hydroxypivalaldehyde solution is added to a trimethylolpropane solution mixed with an acid catalyst. A process for producing -1,3-dioxane.   The high-purity 5-ethyl-2- (1,1-dimethyl-2-hydroxyethyl) -5-hydroxymethyl according to claim 1, wherein the hydroxypivalaldehyde solution and the acid catalyst are simultaneously added to the trimethylolpropane solution. A process for producing -1,3-dioxane.   The high purity 5-ethyl-2- (1,1-dimethyl-2-hydroxyethyl)-according to claim 1, wherein the trimethylolpropane or the trimethylolpropane solution and the acid catalyst are simultaneously added to the hydroxypivalaldehyde solution. A method for producing 5-hydroxymethyl-1,3-dioxane.   The high purity 5-ethyl-2- (1,1-dimethyl-2-hydroxyethyl) -5 according to claim 1, wherein trimethylolpropane mixed with an acid catalyst or a trimethylolpropane solution is added to the hydroxypivalaldehyde solution. -Production method of hydroxymethyl-1,3-dioxane.   6. The high purity 5- according to claim 1, wherein the time for adding either the hydroxypivalaldehyde solution or trimethylolpropane or the trimethylolpropane solution to the other is in the range of 0.5 to 24 hours. A method for producing ethyl-2- (1,1-dimethyl-2-hydroxyethyl) -5-hydroxymethyl-1,3-dioxane.