JPS6160645A - Production of sulfonyl dibenzoic acid - Google Patents

Abstract

PURPOSE:To obtain the titled compound useful as a raw material of polyamide resin, in high yield, by oxidizing diarylsulfone with molecular oxygen in acetic acid solvent, while keeping the ratio of the cobalt catalyst to bromine and the concentration of the catalyst in acetic solvent at specific levels. CONSTITUTION:The objective compound of formula I can be produced by oxidizing the diarylsulfone of formula I with molecular oxygen in acetic acid solvent using a catalyst comprising cobalt and bromine. The amount of the cobalt is 0.2-3wt% in terms of metallic cobalt based on the acetic acid, and the amount of bromine is 1-1.5 equivalent per 1 equivalent of cobalt. The reaction can be carried out under extermely mild conditions, i.e. at about 100 deg.C and atmospheric pressure - about 10kg/cm<2> pressure. The objective compound can be produced in a short reaction time, in high yield, safely and economically in an industrial scale. The reaction liquid can be recycled to the oxidation reaction system after separating the objective compound therefrom and adding diarylsulfone thereto.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for producing sulfonyl dibenzoic acid, and more specifically, a method for producing sulfonyl dibenzoic acid by oxidizing diallylsulfone with molecular oxygen in an acetic acid solvent. It's about how to do it.

Sulfonyl dibenzoic acid is useful as a raw material for polyamide resins.

Polyamide produced using sulfonyl dibenzoic acid exhibits excellent properties such as strength and heat resistance.

(Prior art and its problems) A method for producing sulfonyl dibenzoic acid by oxidizing diallyl sulfone with molecular oxygen in an acetic acid solvent involves using a cobalt salt as a catalyst and reacting at 130°C under pressure to obtain 86% Method for obtaining the desired product in high yield (FRL507,996; CA
70286571), QBI, 005,231; CA
6317983e) or using cobalt organic acid salt and methyl ethyl ketone at 105°C and 300 psI.
(US 3.676.488, C
A77101.202n; US 3,692,828
, CA77151685t), etc. are known.

However, the existing method described above to obtain sulfonyl dibenzoic acid by oxidizing diallyl sulfone requires a long reaction time, the reaction must be carried out under considerable pressure, and the yield is not very good. This method is not satisfactory as a method for industrially producing sulfonyl dibenzoic acid at low cost.

An object of the present invention is to provide an industrially inexpensive method for producing sulfonyl dibenzoic acid that does not have the drawbacks of the existing synthetic methods described above.

(Means for Solving the Problems) As a result of various studies on the oxidation reaction of diallylsulfone in an acetic acid solvent, the present inventor determined that the ratio of the cobalt catalyst to bromine used and the catalyst concentration in the acetic acid solvent should be within a certain range. The present inventors have discovered that when maintained, the oxidation reaction proceeds rapidly even under extremely mild reaction conditions, leading to the completion of the present invention.

That is, the gist of the present invention is to oxidize diallyl sulfone with molecular hydrogen to produce sulfonyl dibenzoic acid using a catalyst in an acetic acid solvent.

The amount of cobalt expressed as cobalt metal in the cobalt salt used as a cobalt salt is in the range of 0.2 to 3 wt% relative to acetic acid, and the amount of bromine used is in the range of an equivalent amount to 1.5 times the equivalent amount of cobalt. I'm busy making things happen.

The method of the invention uses diallylsulfone represented by CH3-1S02ξC113 as a starting material.

Usually, 3,3-dimethyldiphenylsulfone, 3゜4-
Compounds such as dimethyldiphenylsulfone or 4,4-dimethyldiphenylsulfone are frequently used.

These compounds can be prepared, for example, by reacting toluene sulfonyl chloride with toluene in the presence of a Lewis acid catalyst.
Alternatively, it can be produced by a method such as condensing toluenesulfonic acid and toluene in a methanesulfonic acid solvent in the presence of a dehydrating agent.

The reaction of the present invention is carried out in a liquid lower carboxylic acid solvent. Acetic acid is particularly preferred as the lower carboxylic acid solvent.

The amount of the solvent used is 1 to 20 times, preferably 2 to 10 times the amount of diallylsulfone 9.

The catalyst used in the reaction of the present invention is a cobalt salt,
Organic or inorganic cobalt salts are used. Among these cobalt salts, cobalt acetate, cobalt propionate, cobalt benzoate, cobalt naphthenate, etc. are often used.

Regarding the valence of cobalt, divalent cobalt salts are usually used frequently when preparing a reaction solution. The amount of cobalt expressed as cobalt metal in the cobalt salt is preferably in the range of 0.2 to 3 wt% when used in an organic acid solvent such as acetic acid. If the amount of cobalt is less than 0.2 wt%, the reaction rate will be extremely low and it will be difficult for the reaction to actually proceed. If the cobalt concentration exceeds 3 wt%, the reaction will not proceed any more rapidly.Increasing the cobalt concentration any further is not preferable because the loss of cobalt in the post-reaction treatment process will increase. .

Bromine is used as a catalyst along with a cobalt salt.

As bromine, anhydrous hydrobromic acid, molecular bromine, bromine, and compounds are used, but anhydrous hydrogen bromide is usually used.

A solution prepared by dissolving anhydrous hydrobromic acid in an organic acid such as acetic acid is useful for preparing a plate catalyst solution. The amount of bromine used is preferably in the range of 1.5 times the amount of cobalt atoms used in the present day or the amount in the present day.

If the amount of bromine used is less than the equivalent amount of cobalt, the catalyst activity will be low and the reaction rate will be reduced. Also, the equivalent of 1
．． Even if the amount is increased by more than 5 times, the increase in reaction rate will reach a saturation value, resulting in loss of bromine, which is not preferable.

The oxidizing agent used in the method of the present invention is molecular oxygen, and oxygen gas or air is used. When using oxygen gas in the reaction, the reaction may be carried out at normal pressure or slightly pressurized (1,1~x
, 5ky/i), the reaction proceeds at a sufficient rate. Also,
Although the reaction proceeds at normal pressure even when air is used as the oxidizing agent, the reaction is usually carried out under pressure of about 2 to 7 hours.

The temperature at which the reaction is carried out is 90-130°C, usually 10°C.
A temperature range of 0 to 110°C is frequently used. The above-mentioned 5K,
In the method of the present invention, the reaction temperature is around 100°C, and the pressure required for the reaction is mild, ranging from normal pressure to several kg/-, making it extremely safe to carry out the reaction industrially, and requiring simple equipment. I can do it.

The time required for the reaction is, for example, in the range of 1 to 10 hours when the reaction is carried out batchwise, and is usually 2 to 6 hours when the reaction is carried out in normal pressure oxygen.

As the reaction progresses and the target product, sulfonyl dibenzoic acid, is produced, it is precipitated as a solid in the reaction solution. Most of the sulfonyl monobenzoic acid, in which only one of the diallylsulfones has been oxidized, is dissolved in the reaction solution. Therefore, the target product can be isolated by simply allowing the reaction to proceed sufficiently, separating the precipitated solid from the reaction solution, and washing it. After isolation of the target product, diallylsulfone can be added to the reaction solution again to carry out the oxidation reaction repeatedly.

(Implementation row) The present invention will be explained below using examples.

Example-1 Para-toluenesulfonic acid hydrate and an equimolar amount of toluene were added to a methane A/phonic acid solvent to which a pentoxide groove was added, and the mixture was reacted at 25°C for 20 hours. ℃＞'+Yield: 9°C.

A reactor was prepared by adding a stirring rod, a thermometer, a reflux condenser, and an oxygen blowing tube to a five-tube flask as described in Item 11.

Acetic acid 5009 VC"h acid=' Hult (Co(CI-
I3COO)2 ・4l-50) 159 (0,06
16.2 g of an acetic acid solution containing 4.859 (0,075 mol) of hydrobromic anhydride was added. Then 4
．． 4-Dimethyldiphenylsulfone 73.89 (0
, 3 mol) was added, and the solution was heated to 105°C in an air bath outside the reactor. While stirring well, normal pressure oxygen gas was blown in to start the reaction. The reaction solution temperature is 11
The temperature rose to 2°C, and a white solid precipitated out 1.5 hours after the start of the reaction. After continuing the reaction for an additional 2 and a half hours, the oxygen suction was stopped, the reactor was cooled to 50'C, and the white precipitate formed was removed from the house.

The precipitate separated from each house was thoroughly washed with acetic acid and then with warm water for 10 minutes.
Dry under reduced pressure at 0°C to give a white powder of 84.5 ml (yield: 92
h) was obtained. Elemental Analysis Values of White Powder Example-2 An oxidation reaction of 3,4-dimethyldiphenylsulfone was carried out using the same method and reaction conditions as in Example-1. Reaction start 2
Precipitation of a white solid was observed over time. After continuing the reaction for a total of 6 hours, it was cooled, and the precipitate precipitated was washed separately with F to obtain 76.29 g of white powder (82% yield). The obtained powder was identified by elemental analysis and IR spectrum as yolidiphenylsulfone-3,4-dicarboxylic acid.

Example-3 Using the same reaction method as in Example-1, the container used was
A reaction was carried out using an acetic acid solvent of 150- in a flask containing -.

The amount of catalyst used was varied and the concentration of 4,4-dimethyldiphenylsulfone that disappeared through the oxidation reaction was monitored by gas chromatography.

The results obtained are shown in Table-1. Note that cobalt and bromine were used in equivalent amounts.

Table-1 Example-4 Cobalt concentration 1. QNvt% and the concentration of added hydrobromic anhydride was varied to track the rate of disappearance of the raw material.

The results obtained are shown in Table-2.

(Effects of the Invention) According to the method of the present invention, the reaction can be carried out under very mild conditions such as a reaction temperature of around 100°C and a reaction pressure of about 9/d to normal pressure, and the reaction time is shortened. The yield is also high, and sulfonyl dibenzoic acid can be produced advantageously in two steps.

Claims (1)

[Claims] 1) Diallylsulfone represented by the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ is oxidized with molecular oxygen to produce a compound represented by the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ When producing sulfonyl dibenzoic acid, a catalyst composed of cobalt and bromine is used in an acetic acid solvent, and the amount of cobalt expressed as cobalt metal is 0.2 to 3 w per acetic acid.
A method for producing sulfonyl dibenzoic acid, characterized in that the amount of bromine used is in the range of an equivalent amount to 1.5 times the equivalent amount of cobalt.