JPS59184146A - Production of beta-resorcylic acid - Google Patents

Abstract

PURPOSE:To obtain the titled compound economically in a yield equal to that in the conventional method, by reacting resorcinol with a small amount of an inexpensive alkali metal carbonate in an aqueous solution in the presence of CO2 gas, and reutilizing a gas generated in the acid coagulation treatment. CONSTITUTION:Resorcinol is reacted with an alkali metal carbonate in an aqueous solution in the presence of CO2 gas under heating at 80-100 deg.C, and the reaction solution after the completion of the reaction is cooled to 0-50 deg.C to deposit the alkali and separate the alkali from the aqueous layer. The separated alkali is then used together with the above-mentioned alkali metal carbonate. The aqueous layer separated in an acid solution, e.g. sulfuric acid, is then continuously added thereto to carry out the acid coagulation treatment, and deposited crystals of beta-resorcylic acid are separated. CO2 gas generated in the step is reused as part or all of the CO2 gas to be used in the thermal reaction step, and the rate of addition of the separated aqueous layer to the acid solution is preferably adjusted to give the desired feed rate. USE:A raw material for ultraviolet light absorbers.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an industrially advantageous method for producing β-resorcitic acid.

β-resorcitic acid is an ultraviolet absorber such as 2.2', 4
．． 4'-tetrahydroxybenzophenone, 2.2'
It is a compound useful as a raw material for -dihydroxy-4,47-simethoxybenzophenone, etc., and its production method involves mixing resorcin with an alkali metal hydrogen carbonate (e.g., jG(CO, NaHCO, etc.) in a carbon dioxide gas stream. (hereinafter simply referred to as hydrogen carbonate) in a yield of about 50% (Org, Syn, Goe/, Vo/, Q.

557 (1948)) is known.

However, in such a known method, the molar ratio of hydrogen carbonate to resorcin is at least 5 times, and the ratio of hydrogen carbonate to the generated β-resorcinic acid is actually very large, and is therefore not advantageous as an industrial production method. I could not say it.

In view of this, the present inventors investigated to improve the drawbacks of the above-mentioned known methods and produce industrially advantageous ni-β-benzoic acid, and found that an alkali metal instead of hydrogen carbonate If carbonate is used, the amount used is about half a molar amount compared to the case of hydrogen carbonate, and the reaction proceeds with almost the same yield as when hydrogen carbonate is used. Since alkali metal carbonates are generally cheaper than hydrogen carbonates, they have discovered that the amount used can be reduced by about half, making them very economically advantageous, and have thus completed the present invention.

That is, the present invention comprises (a step of heating and reacting Al resorcin in an aqueous solution with an alkali metal carbonate (hereinafter referred to as single E carbonate') at 80 to 100°C in the coexistence of carbonic acid (Bl reaction completed) After that, the reaction solution is cooled to 0 to 50°C to precipitate the alkali and separate it from the aqueous layer (step of precipitating the C1 separated aqueous layer with acid and separating the precipitated β-resolul'dino acid). The present invention provides a method for producing β-resorsi I acid characterized by the following.

According to the method of the present invention, the amount of carbonate used is small. 1. Kamo β-2zo2□ oligoacid. Since the yield is almost the same as that of the conventional method, the desired product can be produced economically.

In addition, in the method of the present invention, the carbon dioxide gas generated in the acid precipitation treatment process is used as part or all of the carbon dioxide gas used in the heating reaction process E, so that raw carbon dioxide gas is virtually unnecessary in terms of raw material cost. By realizing that only a small amount is required, the amount of raw carbonate used can be reduced to about half of the usual amount, and therefore the amount used in this case is lower than that of hydrogen carbonate used in conventionally known methods. Approximately 1/of the amount
The amount is about 4 times the mole, which is very economically advantageous.

The present invention will be explained in detail below.

In the present invention, in the heating reaction in (A) step E, the amount of carbonate used is basically 2.5 to 8.5 times, preferably 2.7 to 8 times, by mole relative to the raw material resorcinol. .

Here, "basic" means the case where the recovered alkali, which will be described later, is not reused, and in the case of reuse, the amount used can be reduced to about 1.2 to 2 moles.

Examples of carbonates include Na□Co, , Co, and Na2COg, and Na2COg is particularly preferably used.

This reaction is carried out in an aqueous solution, but if there is too little water in the reaction system, the reaction rate will decrease, and if there is too much water, the reaction rate will decrease, and the volumetric efficiency will not only deteriorate, but also (B)
Generally speaking, the amount of water is 8 to 12 times the weight of the raw material resorcin, since the alkali recovery rate in the process will be poor.
The amount is preferably 9.5 to 10.5 times by weight, but if the amount is around 10 times by weight, the reaction yield will be poor and the recovery rate of alkali in step (B) will be poor. 2.5 to 2.5 to the normal raw material resorcinol.
5 moles.

The reaction temperature is 80 to 100°C, most preferably 90 to 100°C, especially around 95°C; if this range is exceeded, the reaction rate decreases.

The reaction is carried out by heating and maintaining a predetermined reaction temperature while blowing carbon dioxide into an aqueous solution in which carbonate and resorcinol are dissolved. The temperature is raised to a predetermined reaction temperature while blowing carbon dioxide into the prepared carbonate aqueous solution, and resorcinol is added thereto as a resorcinol aqueous solution with a concentration of 80 to 50%, and the predetermined reaction temperature is maintained while continuing to blow carbon dioxide gas. It is preferable to do it in this way. In this method, it is recommended to add 5 to 15 parts of the total amount of carbonate gas from the preparation of the carbonate aqueous solution to the time of temperature rise, and the rest from the addition of the resorcinol aqueous solution to the time of cooling the reaction solution. Preferably, the feeding rate is slower in the earlier stage than in the later stage, and is preferably maintained at a substantially constant rate in each stage.

Note that the time required to raise the temperature of the carbonate aqueous solution, the time required to add the resorcinol aqueous solution, and the heat retention time are determined appropriately depending on each condition, and are not particularly limited, but generally each is 0.5 to 3 Time, 10-60 minutes, 2-6
It's time.

In the reaction solution obtained after the above heating reaction? Unreacted resorcin, β-resorcidic acid alkali metal salt, unreacted carbonate, and hydrogen carbonate generated from the reaction coexist in the reaction solution, and the reaction solution is cooled to 0 to 50°C, preferably 20 to 40°C. This causes the alkali to precipitate as crystals.

This alkali mainly consists of hydrogen carbonate, with a small amount of unreacted resorcinol and β-resorcin. Contains alkali metal salts and carbonates of sulfuric acid.

A normal solid-liquid separation method is used to separate the alkali from the cooled reaction liquid, but in order to reuse the recovered alkali in the next reaction, the cooled reaction liquid must be
An advantageous method is to allow the crystals to settle in the reaction tank by allowing the mixture to stand for about a minute, and then take out the supernatant liquid as a separated aqueous layer. In this method, the next reaction will be carried out in the reaction tank in which the alkali has been precipitated, so the unreacted fumes contained in the alkali =
β-Resorcin I acid, which is the target product of NosiResorcin 7, is completely recycled together with the alkaline component to the next reaction system, so there is no loss at all.

Through this cooling treatment, 45 to 60% of the carbonate used as a raw material is recovered mainly in the form of hydrogen carbonate.

After the alkali is separated, the separated aqueous layer is acid-precipitated to precipitate β-resorcioleic acid as crystals, but the acid used at this time is not particularly limited if the purpose is only for acid-precipitation treatment. However, when the generated carbonic acid is to be collected and reused, using hydrochloric acid as the acid poses problems such as hydrogen chloride gas being mixed into the carbon dioxide gas, so sulfuric acid is particularly preferably used.

The acid precipitation treatment method itself is carried out according to a known method, but a method in which a separated aqueous layer is added to an acid aqueous solution is preferred.

At this time, in order to use the carbon dioxide gas generated in the acid precipitation treatment for the next reaction, the rate of supply of the separated water layer into the acid aqueous solution must be adjusted so that the amount of carbon dioxide generated is commensurate with the amount of carbon dioxide gas supplied to the reaction. It is preferable to adjust.

The amount of acid used for acid precipitation treatment is usually 1.01 to 1.1 of the theoretical amount.
It is generally added until the pH becomes 2.5 or less.

Further, the acid is usually used as an aqueous solution with a concentration of 10 to 60%, the treatment temperature is generally 60° C. or lower, and the acid is generally maintained at 40°CgL or less after the acid precipitation treatment.

After completion of acid precipitation, β-resorci I acid can be obtained as crystals by separating the precipitated crystals by means such as filtration, and the separated aqueous layer is used as an acid aqueous solution for the next acid precipitation. can do.

Note that the recovered alkali mentioned above has hydrogen carbonate as its main component, but since hydrogen carbonate is a reaction component, if the recovered alkali is to be used as is for the next reaction, it must be used as a new carbonate. is 1.2~ for resorcinol buds.
The amount may be about 2 times the mole, and the amount of raw material carbonate to be used can be significantly reduced. Further, when the carbonic acid gas generated during the acid precipitation treatment is used as part or all of the carbon dioxide gas in the next reaction, part or all of the carbonate gas that is newly used as a reaction raw material becomes unnecessary.

Thus, according to the method of the present invention, the resorcin reaction rate is 5
0-60%, β-resorsi! The target product can be obtained with a yield equal to or higher than that of the conventional method, with an acid selectivity of 95% or more, and the amount of carbonate used is only about half of the conventional method. In the case of recovering carbon dioxide gas and recycling it as a reaction raw material, the amount of carbonate used may be about 174 ml of the conventional method, and carbonate gas as a new reaction raw material may be unnecessary or only a part of it. It is extremely advantageous economically.

Incidentally, an example of a manufacturing apparatus for carrying out the method of the present invention is shown in the first example.
(As shown in the figure, this production equipment is advantageous for recovering alkali and carbon dioxide gas and reusing them.

It is a reaction tank equipped with a supply nozzle 6, each raw material inlet, a reaction mass supernatant liquid (separated water layer) extraction pipe 7, etc. 2 is a separated water layer (acid precipitation raw material) storage tank, 8 is a stirrer, and a mist An acid precipitation tank equipped with a separator, an acid inlet, an acid precipitation raw material inlet, and an acid precipitation mass extraction pipe 8; 4 is an r-filter; 5 is a filtration mother liquor storage tank; 9 is a filtration mother liquor transfer pipe; 10 is a recovery The carbon dioxide gas transfer pipes are shown respectively.

The present invention will be explained below with reference to Examples.

Example 1 990 parts by weight of water was charged into reaction tank 1, and Na
Charge 298 parts by weight of 2COs.

Next, the temperature was raised to 90° C. over 2 hours while blowing COR gas at a rate of 10 parts by weight per hour. Next, while controlling the reaction temperature to be 90 to 95°C, the amount of CO2 gas blown was increased to 20 parts by weight per hour, and 220 parts by weight of a 50% by weight resorcinol aqueous solution was charged over 8° minutes. Thereafter, the temperature was maintained at 95° C. for 8 hours while maintaining the amount of CO2 blown at 20 parts by weight per hour, and then the temperature was cooled to 40° C. over 8 hours. The blowing of CO□ gas is stopped and the mixture is kept under stirring at the same temperature for an additional 80 minutes.

The composition in the reaction tank at this time was: 51 parts by weight of unreacted resortum/syn, 98 parts by weight of Na salt of β-resorsilic acid, 380 parts by weight of Na2GO, Na1(C0°298
．． 4 parts by weight and 1047 parts by weight of water, the resorcin reaction rate was 58.6%, and the β-resono V luciic acid-Na selectivity was 98.0%.

Next, stirring is stopped and the supernatant liquid is transferred to the acid precipitation raw material storage tank 2 after being allowed to stand for 1 hour. Top 68.0 parts by weight, NaHCO
, 78.8 parts by weight and 850 parts by weight of water, remaining in reaction tank 1, 17 parts by weight of NagCOl, and 850 parts by weight of water.
, 220.1 parts by weight and 197 parts by weight of water, and the Na recovered on the solid phase + side was 55-0 in terms of Na2Cog.
It was 2.926 mol as 2.

The solid phase left in reaction tank I was used as a part of the raw material for the following Example 2, and the supernatant liquid was also acid-precipitated as part of the operation in Example 2.

After the acid precipitation is completed, the contents of the acid precipitation tank 8 are filtered through the filter 4, washed twice with 200 parts by weight of water on the filter, and then placed in a vacuum box with an internal temperature of 100°C or higher. When thoroughly dried in a mold dryer, 60.2 parts by weight of white crystals of β-resorcylic acid with a purity of 99.9% were obtained. Acid precipitation, filtration,
The yield after washing with water and drying was 91.92%, and in the end, β-
The amount of Na2CO@ used per 1 m04 of resorcylic acid was 8,188 mol.

Example 2 125 parts by weight of water was charged into acid precipitation tank B, and 98% by weight was added while stirring.
Add 126 parts by weight of % sulfuric acid and adjust the internal temperature to 40°C.

Further, a gas phase line 10 from the acid precipitation tank 8 to the reaction tank 1 is connected.

The solid phase obtained in Example 1 (9.9 parts by weight of unreacted resorcinol, 17.8 parts by weight of β-resorcinic acid-Na, NagC
814 parts by weight of water was charged into a reaction tank 1 containing 7 parts by weight of NaHCO3220, 1 part by weight, and 197 parts by weight of water, and a NλIC0,182 heavy lid part was charged while stirring.

To this, the acid precipitation raw material in the acid precipitation raw material storage tank 2 (the supernatant liquid obtained in Example 1, 41.1 parts by weight of unreacted resorcin),
β-resorcylic acid-Na75.2 parts by weight, Na2CO1
68.0 parts by weight Na2CO 178.8 parts by weight and 85 parts by weight water
(consisting of 0 parts by weight) is fed at a rate of 88 parts by weight per hour for 2 hours (the amount of CO2 produced at this time is 5.0 parts by weight per hour).
2 parts by weight). During this time, the temperature of reaction tank 1 is raised to 90°C. The acid precipitation raw material was increased to 176.6 parts by weight per hour (the amount of CO and gas generated was 10.5 parts by weight per hour) and was supplied for 8 hours and 80 minutes. During this period, for the first 80 minutes, 178 parts by weight of 50% resorcinol aqueous solution was charged into reaction tank L while keeping the internal temperature at 90 r = 95°C, and for the next 8 hours, the internal temperature was kept at 95°C.
Keep it.

Thereafter, the supply amount of the acid precipitation raw material was increased to 102.7 parts by weight (C
The amount of O2 gas produced was reduced to 6.1 parts by weight per hour) and was supplied for about 8 hours. During this time, the temperature of the reaction tank 1 is lowered to 40° C., and at the same time that the acid precipitation raw material is exhausted, the connection line 10 between the acid precipitation tank 8 and the reaction tank 1 is closed, and the temperature is maintained for 80 minutes. The composition in the reaction tank 1 at this time was 49 parts by weight of unreacted resorcinol, 296.2 parts by weight of β-resorlucinic acid-N, and 79 parts by weight of Na2 COB.
Parts by weight, NaHCo, 298.8 parts by weight and 10 parts by weight of water
It consists of 55 parts by weight, and the resorcinol reaction N3 selectivity is 97.
．． It was 64%.

Next, stirring is stopped, and the supernatant liquid is left to stand for 1 hour and transferred to two acid precipitation raw material storage tanks. The supernatant liquid contains unreacted resorcinol 89,8
Weight part, β-Reso! V Rusic acid-N & 77.8 parts by weight Na2COs 62.6
The same phase remaining in the reaction bridge 1 was composed of 9.7 parts by weight of unreacted resorcin, 4 parts by weight of β-resorcin, 178.9 parts by weight of N-HCO, and 863 parts by weight of water. It consists of 316.5 parts by weight of Na2GO, 0.219.9 parts by weight of NλHC, and 195 parts by weight of water, and the Na+ recovered on the solid phase side is composed of Na, Co3
The conversion amount reached 54.88%, and the Na + used per β-resorsi carbonate-Na l moe in the supernatant liquid was N
It was 2B43mod in terms of a2CO1.

On the other hand, the acid precipitation raw material transferred to the acid precipitation raw material storage tank 2 was used for the next reaction and acid precipitation was carried out under the same conditions as in this example.
When washed with water and dried in the same manner as described above, the purity was 9.
62.8 parts by weight of white crystals of 9.9% β-resorsilic acid were obtained. The yield after acid precipitation, filtration, washing with water, and drying was 92.
04%, and the Na 2 CO used per mol of β-resorcylic acid was 8.089 mO#.

Comparative Example 1 990 parts by weight of water was charged into a glass-lined reaction tank,
464 parts by weight of NaHCOs are charged while stirring. Next, while blowing CO2 gas at a rate of 5 parts by weight per hour,
The temperature is raised to 90°C over 2 hours. Reaction temperature is 90-95
While controlling the temperature to be between
Prepare 20 parts by weight over 80 minutes. Thereafter, the temperature was kept at 95° C. for 8 hours while maintaining the amount of CO2 blown at 10 parts by weight per hour. After the heat retention is completed, CO2 is blown in at a rate of 5 parts by weight per hour, and the temperature is cooled down to 40°C over 8 hours. The composition in the reaction tank at this time was 50.4 parts by weight of unreacted resorcin, 8 parts by weight of β-resorcylic acid-Na9B, and Nat.
Consisting of 74 parts by weight of COs, 801.5 parts by weight of NaHCOs and 1078 parts by weight of water, the resorcin reaction rate was 54 parts by weight.
, 2%, β-resorci, acid-NaJi selectivity is 98.4
%, and the amount of Na HCOs required for the production of β-resorlic acid-Na 1mo5 reached 10.86 moe.

280 parts by weight of concentrated sulfuric acid was added to this reaction mass over 4 hours to precipitate the acid, cooled to 40°C, filtered with an offshore filter, washed twice with 200 parts of water on the filter, and then washed internally. warm 1
When thoroughly dried in a vacuum box dryer at temperatures above 00°C, 75.7 parts of white crystals of β-resorcylic acid with a purity of 99.6% were obtained. Acid precipitation ~ yield of dry salt is 91
．． However, compared to that obtained in Example 2, the Na2SO4-based impurities were 0.8% higher.

In addition, the amount of N used per 1 mo1 of β-resorsilic acid was
aHCO, was 11.282 rnol.

NaHCOg, Na2Co3. CO2
A comparison of the amounts of gas and )I2So4 is as shown in the following table.

[Brief explanation of drawings]

FIG. 1 is a flow sheet showing an example of a manufacturing apparatus for carrying out the method of the present invention, and the symbols (1 to 10) in the figure are
is as follows. 1: reaction tank, 2: acid precipitation raw material storage tank, 3: acid precipitation tank. 4: ρ filter, 5: Oki filtration mother liquor storage tank, 6: CO2 supply nozzle, 7: Supernatant liquid extraction pipe, 8: Acid precipitated mass extraction pipe, 9
: Transfer pipe, 10: Carbon dioxide transfer pipe Fig. f

Claims (1)

[Claims] 1) (A) Step (B) of heating and reacting resorcinol in an aqueous solution with an alkali metal carbonate in the presence of carbonic acid at 80 to 100°C. After the reaction is completed, the reaction solution is heated to zero. A β-resorcita characterized by comprising a step of cooling to ~50°C to precipitate an alkali and separating it from an aqueous layer (a step of acid-precipitating the C1 separated aqueous layer and separating the precipitated β-resorcin F acid) Method for producing acid. Carbon dioxide gas generated during the acid precipitation treatment in step 2) and (C) is
(The method according to claim 1, in which carbonic acid is used as part or all of the gas used in the Al process. 8) Claims 1 to 3, in which the acid used for acid precipitation is sulfuric acid.
The method described in Section 2. 4) Acid precipitation is performed by continuously adding a separated aqueous layer to the acid solution, and the generated carbonic acid is separated into the acid solution so that the desired supply rate is achieved as carbon dioxide gas used in the Al process. Method 6) according to claims 2 and 8, comprising adjusting the rate of addition of the aqueous layer. The method described in Items 1 to 4 of