JPH08245464A - Production of 2,2'-dihydroxydiphenylmethane - Google Patents

Abstract

PURPOSE: To selectively and easily produce the subject compound useful as a moisture-hating sealing material, etc., at a low cost from phenol and formaldehyde by a method comprising the combination of a specific catalyst and a specific reaction temperature. CONSTITUTION: Phenol and formaldehyde are subjected to a condensation reaction in the presence (absence) of a catalyst comprising an alkali metal hydroxide or an alkaline earth metal oxide or hydroxide [preferably NaOH, Ca(OH)2 ] at 110-180 deg.C, preferably 130-160 deg.C, to produce the objective compound. The source of the formaldehyde is preferably 35% formaldehyde aqueous solution, and the charging molar ratio of phenol/formaldehyde is preferably 10/1 to 30/1. The catalyst is preferably used in an amount of 100-500ppm based on the charged phenol.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is an isomer of dioxydiphenylmethane (hereinafter referred to as BPF), which has a low hygroscopic property due to its structure. The present invention relates to a method for industrially producing 2,2'-dioxydiphenylmethane (hereinafter referred to as 2,2'-BPF), which is useful in the field, with a high selectivity.

[0002]

2. Description of the Related Art Generally, when phenol and formaldehyde are reacted in the presence of an organic or inorganic acid catalyst, BP
Three isomers of F (2,2 '-, 2,4'-, 4,4 '
A mixture of the (-form) and a higher condensate (novolak) is formed. B made from phenol and formaldehyde
There are various proposals regarding the PF manufacturing method, but the current BP
The purpose of producing F is mainly a method of suppressing the by-product of novolak as much as possible and increasing the yield of BPF. As a method for producing a BPF containing a large amount of one of these three isomers selectively, 4,4'-BPF is prepared by reacting phenol and formaldehyde in a large amount of phosphoric acid. Method of BPF containing 55% 4,4'-BPF / total BPF ratio (Japanese Patent Publication No. 58-177928) and T
4,4'-BPF rich BPF from phenol and formaldehyde using i-Al / zeolite as catalyst
(2,2'-body 1.5%, 2,4'-body 25%, 4,4'-
A body (73%) is disclosed (Japanese Patent Laid-Open No. 63-115830). For 2,2'-BPF, Bu ₂
The method using SnO as a catalyst is "Chemical Abstracts"
104-50604m (1980). However, since saligenol is by-produced in this method, it is extremely difficult to separate and purify 2,2'-BPF from the reaction product, and it cannot be used as an industrial production method.

[0003]

The 2,2'-BPF is
As mentioned above, although its excellent properties have been recognized in the field of applied research, it has not been put to practical use because there is still no suitable industrial manufacturing method. At present, the only conceivable method for producing 2,2′-BPF is a method for fractionally recrystallizing the 2,2′-form from an isomer mixture obtained by ordinary BPF synthesis. The BPF to be obtained usually has an isomer component ratio of 2,4'-form>4,4'-form>2,2'-form, and 2,2'-form is the minimum component. In addition, fractional recrystallization is complicated in operation and low in yield, and is not suitable for industrial implementation.
The present invention solves such a situation, develops the industrial manufacturing method which obtains 2,2'-BPF from phenol and formaldehyde easily and cheaply, and provides it to a market.

[0004]

[Means for Solving the Problems] The reaction factor for synthesizing BPF from phenol and formalin is phenol /
It is considered that there are three formalin charging molar ratios, reaction temperatures, and catalysts, of which the phenol / formalin molar ratio is BP.
It is known that it is a controlling factor of the F / novolak production ratio and does not participate in the isomer ratio. Therefore, the present inventors solved the problem by elucidating and developing the remaining factors (temperature, catalyst). First, the reaction temperature was examined, and the conventional method (hydrochloric acid,
In a method using a protic acid such as sulfuric acid, phosphoric acid or oxalic acid as a catalyst), if the reaction temperature is increased, 2,4 '
It was found that the -body and 4,4'-body decreased and the 2,2'-body increased. Therefore, the reaction conditions for commercial BPF are 80 to 90 ° C in the presence of an acid catalyst, so when the reaction temperature was first raised without a catalyst, the reaction proceeded even without a catalyst if the temperature was sufficiently high, and the isomer ratio of the product was also 2 , 4'-body, 4, 4 '
-It was found that the body decreased and the 2,2'-body moved in the increasing direction. As a result of further investigation, the isomer ratio was found to be the reaction temperature of 110 ° C.
It was found that the temperature gradually began to change after reaching the peak, reached a peak of about 160 ° C, and then leveled off. In order to further improve the selectivity of 2,2'-BPF, the catalyst was examined next to the reaction temperature. As a result, it was found that an alkaline compound promotes the reaction rate and the 2,2'-BPF selectivity, contrary to the case of the normal BPF. It has been found that effective alkaline compounds are oxides and hydroxides of metal elements of Groups 1A and 2A of the Periodic Table, and particularly Group 2A compounds exhibit excellent effects. Based on the above research, the present inventors have completed a selective production method of 2,2′-BPF by combining temperature and a catalyst.

The present invention is characterized by a condensation reaction of phenol and formaldehyde in the presence or absence of an alkali metal hydroxide, an oxide of an alkaline earth metal or a hydroxide at a temperature of 110 to 180 ° C. 2,2'-BPF
Is a manufacturing method of.

As the formaldehyde source used in the present invention, an aqueous formaldehyde solution, particularly a 35% formalin aqueous solution is advantageous. In addition, the molar ratio of phenol / formaldehyde charge of the reaction is such that by-product of novolac is suppressed and B
Since the PF yield is increased, 25/1 to 30/1 is preferable as in the case of commercial BPF. When the molar ratio is smaller than this, the by-product of novolac increases in inverse proportion, and even when it is larger than this, the selectivity of BPF is no longer improved, and meaningless recovered phenol increases in the post-treatment. Become. Therefore, the charged molar ratio of phenol / formalin can be appropriately changed depending on the purpose, that is, whether BPF yield is important or productivity speed (economical) is important, but the industrial range is 10/1 to 30/1. It is suitable. Examples of the alkali metal hydroxide, alkaline earth metal oxide or hydroxide used in the present invention include sodium hydroxide, calcium oxide, magnesium oxide, barium oxide, calcium hydroxide, magnesium hydroxide and barium hydroxide. To be And
The amount added is not particularly limited, but since this substance remains insoluble during the reaction, heating is impaired if the amount used is too large, or filtration after the reaction requires various inconveniences in the operation,
Less than 1% by weight, especially 100 to 500 ppm, relative to the charged phenol
The degree is suitable. As described above, the reaction temperature of the present invention is such that the increase in the production of 2,2'-BPF gradually changes from about 110 ° C and reaches a peak at about 160 ° C.
Although it is between ℃ (thermal decomposition temperature of BPF), industrially, in the case of 35% formaldehyde as a raw material, the reaction temperature is 130 ℃ unless the water and reaction product water are continuously distilled out of the system.
Since it is difficult to maintain the temperature above 180 ° C (phenol boiling point) and is unsuitable because pressurization is required, 110 to 180 ° C is adopted. Particularly, 130 to 160 ° C. is a suitable range. The method of the present invention can be carried out in a batch system or a continuous system, and can be carried out not only in normal pressure-liquid phase but also in various modes such as pressurized-liquid phase, depressurized-gas phase and the like. The post-treatment method was as follows. The reaction solution obtained as described above was distilled under reduced pressure to give a crude fraction, followed by a crude
A 2'-BPF fraction is obtained. This was recrystallized from 10 to 50% by weight of methanol water and dried to obtain 2,2'-BPF.
Obtained with a purity of 99% or higher.

The method of the present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. The composition analysis of BPF in the examples was performed by an absolute calibration curve method using a high performance liquid chromatogram.

[0008]

Example 1 196 parts by weight of phenol and catalyst C in a flask
a (OH) ₂ 500ppm (total amount of charged phenol) was charged and stirred at the set temperatures of 120 ° C, 140 ° C and 160 ° C respectively, and 30.2 parts by weight of phenol and 35% formalin were added thereto.
13.8 parts by weight (molar ratio = 14.9 / 1) of the mixed solution is added dropwise over 2 hours (water is distilled out of the system as needed to maintain the set temperature during that time), and the set temperature is maintained to maintain the liquid composition. React until there is no change. Table 1 shows the analysis results of the reaction solution.

[0009]

[Table 1]

As is clear from these results, when the reaction temperature is raised, the selectivity to the 2,2'-form and the reaction rate also increase.
At 0 to 160 ° C, the production of 2,2'-form is significantly increased.

[0011]

Example 2 In a test tube, an alkali metal hydroxide shown in Table 2 below,
1 part by weight of alkaline earth metal oxides or hydroxides thereof, 18.8 parts by weight of phenol, and 1.2 parts by weight of 35% formalin (molar ratio 14.3 / 1) were charged, and the mixture was kept at 120 to 135 ° C for 3 hours. Table 2 shows the analysis results of the reaction solution.

[0012]

[Table 2]

As is clear from these results, the alkali metal hydroxide, alkaline earth metal oxide or hydroxide is 2,
It exerts an excellent effect on the selective production of 2'-form.

[0014]

Example 3 The reaction temperature was fixed at 160 ° C. and the catalyst Ca (O
H) ₂ was 50 ppm, 500 ppm, and 1000 ppm, and the reaction was carried out by the same operation as in Example 1. Table 3 shows the analysis results of the reaction solution.

[0015]

[Table 3]

As is clear from these results, the addition of the catalyst of the present invention selectively produces the 2,2'-form.

[0017]

Example 4 In the same manner as in Example 1, 1 weight part of phenol and 500 ppm of catalyst (based on total phenol) were charged into a flask and stirred at 160 ° C., and phenol / phenol was added at the end of dropping. Formalin molar ratio is 5 / 1,15 / 1,30
A mixture of phenol and formalin in an amount calculated to be / 1 was added dropwise over 2 hours, and the reaction was carried out for 2.5 hours while maintaining the same temperature. Table 4 shows the analysis results of the reaction solution.

[0018]

[Table 4]

From these results, the formation of the 2,2'-form is more excellent when the molar ratio of phenol to formaldehyde is 15 to 30.

[0020]

Example 5 <Apparatus> 1 inch reaction tube made of SUS (height 1.2 m), thermometer protection tube of 10 mm in the center, 450 ml of Raschig ring 5 × 5 mm was packed around it, raw material supply pump at the bottom, tower top Equipped with an overflow pipe to the pressure receiver, the system pressure can be adjusted with N ₂ . A 2.5-inch mantle with a mantle heater coating is installed on the outside. <Reaction> From the bottom, the phenol / formalin molar ratio is 15 /
The mixed solution of 1 was supplied at LSV 0.8 g / cc / H, and the reaction solution was discharged from the top of the tube into the receiver while overflowing the temperature at 160 ° C.
A continuous reaction was carried out for 100 hours while maintaining a pressure of 2 kg / cm ² (pressurized with N ₂ ). The reaction solution in a steady state (10 to 100 hours) was distilled under reduced pressure to obtain 300 g of a BPF fraction. The composition of the obtained BPF was 2,2'-form 73%, 2,4'-form 25.5%, 4,4'-form.
At 1.5%, the yield was 62% (vs. formalin charged).
2,2'-BPF obtained by recrystallizing this from the same amount of methanol aqueous solution (concentration 25 wt.%) Was 166.4 g, and the yield was 77.4% (relative to existing) and the purity was 99.2%.

[0021]

Example 6 <Apparatus> A glass reaction tube (internal diameter: 2.9 cm, height: 40 cm, central portion filled with 5 × 5 mm Raschig ring 80 ml). The top part is equipped with a dephlegmator, a distilling pipe, a receiver connected to a vacuum line, a raw material supply port in the middle of the filling part, and a 500 ml reaction solution reservoir flask (with a vacuum suction port for withdrawing the internal solution at any time) at the bottom part. A ribbon heater and a mantle heater are used to heat the reaction tube and flask. <Reaction> 200 g of phenol was charged into a flask, boiled, the system was gradually depressurized, and the Raschig ring filling section was adjusted to a predetermined temperature. After the system temperature has settled down, the molar ratio is 15
The blended phenol / formalin of / 1 was supplied from the feed port at an LSV of 0.23 g / cc / hr, and the continuous reaction was carried out while continuously distilling the water produced by the reaction and the water containing the formalin from the top of the column. Table 5 shows the isomer ratio of the BPF produced in the steady state when the packed bed temperature was 100, 120 and 150.

[0022]

[Table 5]

[0023]

INDUSTRIAL APPLICABILITY The method for producing 2,2'-BPF of the present invention is an industrially excellent method for selectively producing an industrially valuable 2,2'-form by an easy and inexpensive method. Is.

Claims (1)

[Claims] 1. Selective condensation reaction between phenol and formaldehyde in the presence or absence of an alkali metal hydroxide, an oxide of an alkaline earth metal or a hydroxide at a temperature of 110 to 180 ° C. 2. , 2'-Dioxydiphenylmethane production method.