JP2007246444A - Method for producing (meth)acrylic ester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for previously predicting or evaluating the degree of color tone of an acrylic or a methacrylic ester to be a product without acrylating a polyhydric alcohol which is a raw material in a method for producing the acrylic or methacrylic ester comprising subjecting acrylic or methacrylic acid and the polyhydric alcohol to a condensation reaction and to provide the method for producing the acrylic or methacrylic ester using the method. <P>SOLUTION: The method for production is a method for producing the acrylic or methacrylic ester comprising subjecting the acrylic or methacrylic acid and the polyhydric alcohol to the condensation reaction. The method comprises (1) a step of measuring the degree of coloring of a phthalic acid resin with the polyhydric alcohol (JIS K 1510), (2) a step of predicting the color tone of the acrylic or methacrylic ester based on the degree of coloring of the phthalic acid resin measured in the (1) and (3) a step of producing the acrylic or methacrylic ester having the color tone from the acrylic or methacrylic acid and the polyhydric alcohol based on the prediction of the color tone in the (2). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a (meth) acrylic acid ester by condensation reaction of (meth) acrylic acid and a polyhydric alcohol, and evaluating the phthalic acid resin coloring degree of the raw polyhydric alcohol to obtain a desired color tone. The present invention relates to a method for producing a (meth) acrylic acid ester having a range.

  Conventionally, production methods of (meth) acrylic acid esters include dehydration esterification reaction of (meth) acrylic acid and alcohol, transesterification reaction of alkyl (meth) acrylate and alcohol, or ( Addition reaction of (meth) acrylic acid is generally performed. Among these, the dehydration esterification reaction is a useful production method because (meth) acrylic acid ester is easy to produce and there are various types of (meth) acrylic acid ester that can be produced.

  In the method for producing a (meth) acrylic acid ester using this dehydration esterification reaction, coloring of the produced (meth) acrylic acid ester may become remarkable due to impurities contained in the raw material alcohol. there were. When such coloring occurs, there are inconveniences such as polarization of transmitted light, absorption of a specific wavelength and a decrease in reflectance when used in an optical material, and poor toning when used in a coating material.

  Dipentaerythritol, ditrimethylolalkane and the like are widely used as raw material alcohols (particularly polyhydric alcohols), and these are usually alkali metal hydroxides or alkaline earths as described in Patent Document 1. It is produced by condensing a metal hydroxide, formaldehyde, and a predetermined alkanal.

  In the polyhydric alcohol obtained by this manufacturing method, even if it passes through a refinement | purification process, the trace amount impurity derived from this manufacturing method is contained, and this affects the coloring of (meth) acrylic acid ester which is a product It was considered. Moreover, although polyhydric alcohols are usually commercially available, there has been a problem that the degree of coloring of the (meth) acrylic acid ester produced varies depending on the supplier and the lot.

  Therefore, it is extremely useful industrially if the degree of coloring of the product (meth) acrylic acid ester can be predicted or evaluated at the stage of the raw material polyhydric alcohol.

By the way, as a means for evaluating the degree of coloring of alkyd resin or the like using pentaerythritol, phthalic acid resin coloring degree according to JIS K 1510 is known. Specifically, the degree of phthalic acid resin coloring is a colorimetric evaluation of the degree of coloring of a resin obtained by reacting pentaerythritol with phthalic anhydride.
Japanese Patent Laid-Open No. 1-444689

  In the method for producing a (meth) acrylic acid ester by condensation reaction of (meth) acrylic acid and a polyhydric alcohol, the present invention becomes a product in advance without acrylated the raw polyhydric alcohol (meth). It is an object of the present invention to provide a method for predicting or evaluating the degree of color tone of an acrylate ester and a method for producing a (meth) acrylate ester using the method.

  As a result of intensive studies to solve the above problems, the present inventor has obtained the following knowledge.

  Measure the degree of phthalic acid resin coloring of the starting polyhydric alcohol (dipentaerythritol, etc.) and measure the degree of coloring of the (meth) acrylic acid ester obtained by condensation reaction of the polyhydric alcohol and (meth) acrylic acid. As a result, it was found that the result of the phthalic acid resin coloring degree of the polyhydric alcohol and the result of coloring the (meth) acrylic acid ester are well correlated. Moreover, when a polyhydric alcohol having a phthalic acid resin coloring degree of 2 or less in terms of Gardner color as defined in JIS K 1510 is used as a raw material, the color tone of the (meth) acrylic ester produced is 50 or less in APHA color. I found out that Based on this knowledge, further studies have been made and the present invention has been completed.

  That is, this invention provides the manufacturing method of the following (meth) acrylic acid esters.

Item 1. A method of producing a (meth) acrylic acid ester by a condensation reaction of (meth) acrylic acid and a polyhydric alcohol,
(1) a step of measuring a phthalic acid resin coloring degree (JIS K 1510) of a polyhydric alcohol,
(2) a step of predicting the color tone of the (meth) acrylic acid ester based on the phthalic acid resin coloring degree measured in (1), and (3) (meth) acrylic acid based on the color tone prediction of (2). The manufacturing method including the process of manufacturing the (meth) acrylic acid ester which has this color tone from a polyhydric alcohol.

  Item 2. Item 2. The method according to Item 1, wherein the polyhydric alcohol is solid at room temperature.

  Item 3. Item 3. The production method according to Item 1 or 2, wherein the polyhydric alcohol has pentaerythritol 1-trimer as a main component.

  Item 4. Item 4. The production method according to any one of Items 1 to 3, wherein the polyhydric alcohol contains 80% or more of dipentaerythritol.

  Item 5. Item 5. The production method according to any one of Items 1 to 4, wherein the polyhydric alcohol has a phthalic acid resin coloring degree of 2 or less Gardner colors.

  Item 6. Item 6. The production method according to Item 5, wherein the color tone of the produced meth) acrylic acid ester is 50 or less APHA colors.

  Item 7. In the case of producing a (meth) acrylic acid ester by condensation reaction of (meth) acrylic acid and a polyhydric alcohol, the polyhydric alcohol is measured by measuring the degree of phthalic acid resin coloring (JIS K 1510) of the polyhydric alcohol. And a method for predicting the color tone of (meth) acrylic acid ester produced from (meth) acrylic acid.

  Item 8. A method of producing a (meth) acrylic acid ester by selecting a polyhydric alcohol having a phthalic acid resin coloring degree (JIS K 1510) of 2 or less Gardner colors and subjecting the polyhydric alcohol and (meth) acrylic acid to a condensation reaction. .

  In the present specification, “(meth) acrylic acid” means acrylic acid and / or methacrylic acid, and “(meth) acrylic acid ester” means acrylic acid ester and / or methacrylic acid ester. To do.

  The present invention is described in detail below.

In the method for producing a (meth) acrylic acid ester of the present invention, (1) a step of measuring a phthalic acid resin coloring degree (JIS K 1510) of a polyhydric alcohol,
(2) a step of predicting the color tone of the (meth) acrylic acid ester based on the phthalic acid resin coloring degree measured in (1), and (3) (meth) acrylic acid based on the color tone prediction of (2). And a step of producing a (meth) acrylic acid ester having the color tone from polyhydric alcohol.

  By using this method, since the color tone of the (meth) acrylic acid ester can be predicted depending on the degree of phthalic acid resin coloring of the polyhydric alcohol, there is an advantage that the color tone of the product can be predicted without being acrylated. Therefore, it is effective for selection of the raw material polyhydric alcohol, and there is an advantage that an acrylate having a low color tone can be obtained by using the raw material.

  First, the polyhydric alcohol used in the first step (1) includes a diol and a polyol having three or more hydroxyl groups.

  Specific examples of the diol include, for example, ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, diethylene glycol, dipropylene glycol, Ethylene glycol, tripropylene glycol, tetraethylene glycol, 1,4-dihydroxycyclohexane, neopentyl glycol, neopentyl glycol ethylene oxide adduct, neopentyl glycol propylene oxide adduct, bisphenol A ethylene oxide adduct, bisphenol A Propylene oxide adduct, hydrogenated bisphenol A ethylene oxide adduct, hydrogenated bisphenol A propylene oxide adduct, bisphenol F Chi alkylene oxide adducts, tricyclodecane dimethylol, and the like.

  Specific examples of triols include glycerin, glycerin ethylene oxide adduct, glycerin propylene oxide adduct, trimethylolpropane, trimethylolpropane ethylene oxide adduct, trimethylolpropane propylene oxide adduct, and the like. .

  Specific examples of polyols include, for example, ditrimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol, ethylene oxide adducts of these polyols, propylene oxide adducts of polyols, tris-2-hydroxyethyl isocyanurate, and the like. Can be mentioned.

  Among these polyhydric alcohols, polyols that are solid at normal temperature (for example, 10 to 30 ° C.) are preferable. Specifically, ditrimethylolpropane (melting point: 105 to 115 ° C.), dipentaerythritol (melting point: 210 to 220). ° C), pentaerythritol (melting point: 260 ° C), tris (2-hydroxyethyl) isocyanurate (melting point: 250-320 ° C), and the like.

  Of these, polyhydric alcohols preferably contain pentaerythritol 1-3-mer as a main component, and more preferably contain 80% by weight or more of dipentaerythritol.

  These polyhydric alcohols are commercially available or can be easily prepared.

  The polyhydric alcohol as the raw material is evaluated according to the phthalic acid resin coloring degree defined in JIS K1510. In the present invention, the degree of phthalic acid resin coloration is measured by adding phthalic anhydride to a sample (polyhydric alcohol) and comparing the color of the resin product produced when heated with a colorimetric standard solution. Displayed in Gardner colors. Specifically, Example 1 may be referred to.

  In the step (2), the color tone of the (meth) acrylic acid ester is predicted based on the phthalic acid resin coloring degree measured in the above (1).

  The phthalic acid resin coloring degree of the polyhydric alcohol measured in the first step (1) is high with the color tone (APHA color number) of the (meth) acrylic ester produced from the polyhydric alcohol and (meth) acrylic acid. Correlation. Therefore, it is possible to predict the color tone of the (meth) acrylic acid ester with high accuracy from the degree of phthalic acid resin coloring of the polyhydric alcohol. Thereby, there exists a merit that the color tone of (meth) acrylic acid ester can be estimated before acrylate-ization of this polyhydric alcohol of a raw material.

  For example, when the phthalic acid resin coloring degree of the polyhydric alcohol is Gardner color number 1, APHA color number is 40 or less (particularly 20-30), and when Gardner color number 2 is 2, APHA color number is 40-50. When the Gardner color number is 3 or more, the APHA color number exceeds 100, and the degree of coloring increases.

  Therefore, in order to suppress the color tone of the (meth) acrylic ester to 50 or less APHA colors, a polyhydric alcohol having a phthalic acid resin coloring degree of 2 or less Gardner colors is selected. Furthermore, in order to suppress the APHA color number to 40 or less, a polyhydric alcohol having a Gardner color number of 1 or less is selected.

  In particular, in the case where a solid polyol is used at the normal temperature (for example, 10 to 30 ° C.), the correlation is high.

  In the third step (3), a (meth) acrylic acid ester having the color tone is produced from (meth) acrylic acid and a polyhydric alcohol based on the color tone prediction of (2).

  A method of producing a (meth) acrylic acid ester from a polyhydric alcohol whose phthalic acid resin coloring degree is measured and (meth) acrylic acid can be performed, for example, as follows.

  Examples thereof include a method of heating and stirring (meth) acrylic acid and a polyhydric alcohol in the presence of an acidic catalyst.

  The reaction ratio of the polyhydric alcohol and (meth) acrylic acid may be determined as appropriate, but the molar ratio of (meth) acrylic acid to 1 mol of hydroxyl group in the polyhydric alcohol is about 0.9 to 1.8, preferably What is necessary is just to be about 1.1-1.5. The most suitable ratio between the polyhydric alcohol and (meth) acrylic acid varies depending on the type of polyhydric alcohol and reaction conditions, but can be easily set by an experimental method.

  Examples of the acidic catalyst include sulfuric acid, paratoluenesulfonic acid, methanesulfonic acid and the like. The usage-amount of a catalyst should just be the range of 0.01-10.0 weight% with respect to the total amount of a polyhydric alcohol and (meth) acrylic acid.

  As the organic solvent used in the present invention, benzene, toluene, xylene, cyclohexane, n-heptane and the like can be used alone or in combination of two or more, but toluene alone is preferable from the viewpoint of handling.

  Moreover, what is necessary is just to set reaction temperature suitably according to the compound to be used and the objective, About 70 to 140 degreeC, Preferably it is about 70 to 90 degreeC. The reaction pressure is, for example, 45 kPa to normal pressure, preferably about 50 to 60 kPa, and the reaction time is usually 8 to 20 hours.

  In the above reaction, a polymerization inhibitor can be added to the reaction solution for the purpose of preventing polymerization of the resulting (meth) acrylic acid ester. Examples of such polymerization inhibitors include inorganic polymerization inhibitors such as cuprous oxide, cupric oxide, cuprous chloride, cupric chloride, hydroquinone, hydroquinone monomethyl ether, tert-butylcatechol, t- Organic polymerization inhibitors such as butylhydroquinone, 2,4-dimethyl-6-tert-butylphenol, 2,6-tertbutyl-p-cresol, parabenzoquinone, 2,5-diphenylparabenzoquinone, phenothiazine, diphenylamine are used. . Among these, hydroquinone monomethyl ether is preferably used as a polymerization inhibitor with little coloration during product storage and use. The usage-amount of these polymerization inhibitors should just be about 100-2000 mass ppm with respect to the reaction liquid.

  The reaction has a reaction rate of 80 to 95 based on the consumption of (meth) acrylic acid from the viewpoint that if the reaction proceeds too much, a side reaction proceeds and the color tone after acrylate formation increases. %, Preferably about 85 to 92%. Here, the “reaction rate based on the consumption of (meth) acrylic acid” is the ratio (mol%) of the number of moles of (meth) acrylic acid consumed to the number of moles of hydroxyl groups of the starting polyhydric alcohol. Means. This reaction rate is calculated by measuring the acid value in the reaction solution.

  After completion of the esterification reaction, the acid content of the reaction solution is neutralized. In order to suppress ester decomposition (sapon value) at the time of neutralization with an alkaline aqueous solution, it is preferable to add water (distilled water) or a neutral salt aqueous solution and perform a water washing treatment before the neutralization treatment. The neutralization treatment step may be performed according to a conventional method, and examples thereof include a method in which an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide is added to the reaction solution, followed by stirring and mixing. In this case, the amount of the alkali component is usually 1 time or more, preferably 1.1 to 1.6 times in molar ratio with respect to the acid content of the reaction solution. Furthermore, the water washing treatment process may be performed according to a conventional method, and examples thereof include a method of adding water to the reaction solution after the neutralization treatment, stirring and mixing.

  After the water washing treatment and the neutralization treatment, the organic layer containing the (meth) acrylic acid ester produced is separated, and then the organic solvent is removed from the organic layer by a known method to obtain (meth) acrylic acid. The ester is obtained.

  The (meth) acrylic acid ester obtained in this way has a color tone (APHA color number) within a range predicted from the phthalic acid resin coloring degree of the raw material polyhydric alcohol.

  According to the present invention, the color tone of (meth) acrylic acid ester as a product can be predicted prior to acrylate formation by measuring the degree of phthalic acid resin coloring of polyhydric alcohol. In addition, since the color tone of the (meth) acrylic acid ester can be easily evaluated at the stage of the raw material polyhydric alcohol, a desired low-colored acrylate having a low color tone can be easily and efficiently obtained. Therefore, the present invention can be said to be an industrially significant production method.

  Next, the present invention will be described in more detail with reference to comparative examples, but the present invention is not limited thereto.

Example 1
As the alcohol, dipentaerythritol manufactured by Company A was used, and the phthalic acid resin coloring degree defined in JIS K 1510 was carried out.

  That is, 3.0 g of dipentaerythritol and 5.4 g of phthalic anhydride were put in a test tube and mixed well, and then heated at 260 to 265 ° C. with occasional shaking for 5 minutes. The phthalic acid used here is specified in JIS K 4128, and has a Hazen value of 30 or less after the above heating conditions. As the color tone of the obtained resin product, the Gardner color number was 1.

Example 2
Exactly the same operation as in Example 1 was performed, except that dipentaerythritol manufactured by Company B was used as the alcohol. As the color tone, the Gardner color number was 1.

Example 3
The same operation as in Example 1 was performed except that dipentaerythritol manufactured by C company was used as the alcohol. As the color tone, the Gardner color number was 1.

Example 4
The same operation as in Example 1 was performed except that dipentaerythritol manufactured by D company was used as the alcohol. As the color tone, the Gardner color number was 1.

Example 5
Exactly the same operation as in Example 1 was performed except that dipentaerythritol manufactured by E company was used as the alcohol. As the color tone, the Gardner color number was 2.

Example 6
Exactly the same operation as in Example 1 was performed except that dipentaerythritol manufactured by F company was used as the alcohol. As the color tone, the Gardner color number was 1.

Example 7
Exactly the same operation as in Example 1 was performed except that dipentaerythritol manufactured by G company was used as the alcohol. As the color tone, the Gardner color number was 2.

Example 8
The same operation as in Example 1 was performed except that dipentaerythritol manufactured by Company H was used as the alcohol. As the color tone, the Gardner color number was 1.

Example 9
Exactly the same operation as in Example 1 was performed except that dipentaerythritol manufactured by I company was used as the alcohol. As the color tone, the Gardner color number was 2.

Reference example 1
Exactly the same operation as in Example 1 was performed except that dipentaerythritol manufactured by J Company was used as the alcohol. As a color tone, the Gardner color number was 3.

Reference example 2
The same operation as in Example 1 was performed except that dipentaerythritol manufactured by K company was used as the alcohol. As a color tone, the Gardner color number was 3.

Test example 1
Using dipentaerythritol used in Examples 1 to 9 and Reference Examples 1 and 2, acrylated was performed as follows.
(1) Reaction process In a 2 L reactor equipped with a stirrer, a thermometer, and a Dean-Stark apparatus, 357 g (1.41 mol) of dipentaerythritol, 729 g (10.13 mol) of distilled acrylic acid, 595 g of toluene, and second chloride. 1.7 g of copper and 17 g of 78% sulfuric acid were charged, and a dehydration esterification reaction was performed by heating the reactor under a pressure of 54 kPa. The reaction rate based on the consumption of acrylic acid was 90%. The reaction time under these conditions was 10 hours.
(2) Neutralization step After cooling the reaction solution, 1000 g of toluene was added for dilution. The reaction solution thus obtained was transferred to a tank for neutralization treatment, added with 400 g of distilled water, sufficiently stirred and then allowed to stand to remove the separated lower layer.

In order to neutralize the acid content of the upper layer, 400 g of a 20% aqueous sodium hydroxide solution was added and stirred sufficiently, and then allowed to stand to remove the separated lower layer. Further, 400 g of a 20% aqueous sodium hydroxide solution was added and stirred sufficiently, and then allowed to stand to remove the separated lower layer.
(3) Water Washing Step 500 g of distilled water was added to the upper layer and stirred sufficiently, and then allowed to stand to remove the separated lower layer.
(4) Solvent removal step 400 ppm of hydroquinone monomethyl ether was added to the upper layer, and the solvent was removed under reduced pressure until the toluene concentration was 1% or less while blowing air. 8.4 g of Radiolite # 200 (manufactured by Showa Kagaku Kogyo) was added to 500 g of the obtained crude acrylate, and the mixture was well stirred and mixed. The mixture was passed through qualitative filter paper no. An acrylate was obtained by filtration with a pressure filtration apparatus equipped with 2.

  The acrylate thus obtained was subjected to turbidity measurement using a 2100AN turbidimeter (manufactured by HACH). In this measurement, the apparatus was calibrated using formazine as a reference substance, and turbidity (NTU) was measured using the 90 ° side scattered light method as a measurement principle. If the turbidity of the acrylate was 7 NTU or less, it was judged to be transparent and subjected to physical property measurement.

Test example 2
Table 1 shows the test results of the phthalic acid resin coloring degree of the raw material alcohols in Examples 1 to 9 and Reference Examples 1 and 2, and the values obtained by converting the color tone of the acrylate obtained from the raw material alcohols by APHA.

  As shown in this result, it was found that the state of coloring of the phthalic acid resin coloring degree of the raw material alcohol and the state of the color tone of the acrylate produced using the raw material alcohol have a very high correlation. The color tone of the acrylate produced from the raw material alcohol having a phthalic acid resin coloring degree of Gardner 2 or less was 50 or less, and the coloring was at a low level.

  On the other hand, the color tone of the acrylate produced from the raw material alcohol of Gardner 3 was 100 or more in terms of the phthalic acid resin coloring degree, and the coloring was at a high level.

  That is, in order to obtain an acrylate having a low color tone, it has been found that a raw material alcohol having a Gardner of 2 or less, further 1 or less, may be used in a phthalic acid resin coloring degree test.

  In addition, Table 2 shows physical property values of dipentaerythritol of each company used in Examples 1 to 9 and Reference Examples 1 and 2.

  A blank in Table 2 indicates that there is no data. From Table 2, the physical property value of dipentaerythritol was not confirmed to correlate with the coloration of (meth) acrylic acid ester.

  Therefore, it was found that the coloration of (meth) acrylate was estimated only after the phthalic acid coloring test was conducted. This is considered to be because coloring is caused by an unknown trace component contained in dipentaerythritol.

  Each company's alcohol was solid (white powder to white flakes), and there was no difference in appearance.

Claims (8)

A method of producing a (meth) acrylic acid ester by a condensation reaction of (meth) acrylic acid and a polyhydric alcohol,
(1) a step of measuring a phthalic acid resin coloring degree (JIS K 1510) of a polyhydric alcohol,
(2) a step of predicting the color tone of the (meth) acrylic acid ester based on the phthalic acid resin coloring degree measured in (1), and (3) (meth) acrylic acid based on the color tone prediction of (2). The manufacturing method including the process of manufacturing the (meth) acrylic acid ester which has this color tone from a polyhydric alcohol.   The production method according to claim 1, wherein the polyhydric alcohol is solid at room temperature.   The production method according to claim 1 or 2, wherein the polyhydric alcohol is composed mainly of pentaerythritol 1-trimer.   The production method according to any one of claims 1 to 3, wherein the polyhydric alcohol contains 80% or more of dipentaerythritol.   The production method according to any one of claims 1 to 4, wherein the polyhydric alcohol has a phthalic acid resin coloring degree of 2 or less Gardner colors.   The production method according to claim 5, wherein the color tone of the produced meth) acrylic acid ester has an APHA color number of 50 or less.   In the case of producing a (meth) acrylic acid ester by condensation reaction of (meth) acrylic acid and a polyhydric alcohol, the polyhydric alcohol is measured by measuring the degree of phthalic acid resin coloring (JIS K 1510) of the polyhydric alcohol. And a method for predicting the color tone of (meth) acrylic acid ester produced from (meth) acrylic acid.   A method of producing a (meth) acrylic acid ester by selecting a polyhydric alcohol having a phthalic acid resin coloring degree (JIS K 1510) of 2 or less Gardner colors and subjecting the polyhydric alcohol and (meth) acrylic acid to a condensation reaction. .