JPS5932453B2 - Method for alkaline melting of aromatic sulfonate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a corresponding aromatic oxy compound by melting an aromatic sulfonate with an alkali.
The so-called alkali melting reaction, in which the corresponding aromatic oxy compounds are obtained by melting with acids , , , , , , , and , is still an industrially practiced method for producing aromatic oxy compounds.

For example, in 1970-9970, Kotspers Company Incorporated produced benzene-1 and 3.
- An alkali melting reaction between disulfonic acid disodium and caustic soda is carried out. However, the high viscosity region that occurs during the reaction has been overcome by using a kneader-type kneading mixing reactor, which is equipped with a 400-gallon melting pot and a 150 horsepower stirring motor,・ 3000 l of 3-disulfonic acid disodium,
When charging 1800lb of caustic soda, the maximum load is 60
000W.

The alkali-melted reaction product obtained by this method is in a powder state and is discharged from the tea garden, but just before the reaction content becomes powder, it becomes highly viscous when it contains a certain percentage of water. Therefore, in order to overcome this situation, a very strong stirring force was applied to solve the problem. Various difficulties are expected when implementing such a large stirring power and the accompanying special reaction equipment such as a kneader on an industrial scale.

In order to avoid this problem, the viscosity of the alkali-molten reactant may be reduced by some method. For example, in PB Report 74051 (G56-3) 295, the alkaline melting reaction of benzene-1-carboxylic-3-5-disulfonic acid was carried out by charging 50% caustic soda 1500 and 9 to 90% caustic potassium 300 while heating in a 60001 cast steel reaction pot. 9 (100%) and benzene-1-carboxy 3-5-disulfonic acid
) is added to complete the alkali melting reaction. In other words, caustic alkali is used in far excess of the theoretical amount,
Also, by mixing caustic soda and caustic potash, the viscosity of the alkali-molten reactant is reduced. However, this method is also not noteworthy from the point of view of product cost, such as increasing the amount of extra neutralizing agent to neutralize excess alkali in the process of treating the reaction product and increasing the number of treatment steps. Furthermore, as recognized in Japanese Patent Publication No. 46-38486, when disodium benzene-1,3-disulfonate is melted with an alkali, a third substance that is stable at the alkali melting temperature and has the effect of lowering the viscosity, such as benzenesulfone, is used. A method is used in which an alkali melting reaction is made into a liquid by adding sodium acid, sodium toluenesulfonate, or a metal salt of phenol or cresol as a diluent.

This method of adding a third substance has the effect of reducing the amount of alkali used, liquefying the alkali-melting reaction product, and allowing the alkali-melting reaction of disodium benzene 1,3-disulfonate to be carried out with relatively low stirring power. A large amount of substances other than the product originally intended for manufacture, such as the above,
In No. 6-38486, it becomes necessary to produce or recycle phenol, cresol, etc. other than resorcinol.

Therefore, as a result, the productivity of resorcin is reduced, and a step of separating resorcin and additives is required, so that it cannot be said to be an industrially advantageous method. In this way, the state of the alkali molten reactant of aromatic sulfonate, in which the alkali molten reactant is essentially a powder, changes from liquid to slurry to high viscosity region to powder, and in order to overcome this high viscosity region, Although various methods as mentioned above have been taken to avoid or avoid this, they each have their own drawbacks and should not be satisfied from an industrial standpoint.

The present inventors charged an aromatic sulfonate powder, which is essentially a powder, into a pot, heated it while stirring to set the content to a predetermined temperature, and then maintained the content in a powder state at all times. By adding flakes of caustic at a rate of
We have completed the present invention by discovering that the stirring load can be increased in a normal alkali melting apparatus with no significant difference from that in dry operation, and aromatic oxy compounds can be advantageously obtained.

In the present invention, when an aromatic sulfonate in which the alkali-melted reaction product is essentially a powder is melted in an alkali to obtain a corresponding aromatic oxy compound, the molten reaction product is always in the form of a powder in the powdered aromatic sulfonate. This is a method of alkali melting aromatic sulfonate, which is characterized by adding caustic alkali at a rate that maintains the state, and the reaction can proceed in a powder state throughout the reaction without passing through a high viscosity region during the reaction. It is characterized by

The aromatic sulfonates applicable to the present invention include all those whose alkali-melted reaction product is essentially a powder, such as 5-sulfoisophthalic acid, biphenyl-4,4'
-disulfonic acid, benzene-1-1●3-disulfonic acid, benzene-1-carboxy-3,5-disulfonic acid, naphthalene-1,5-disulfonic acid, and other alkali metal salts, but the present invention is not limited to these. It's not something you can do.

These aromatic sulfonate powders may contain some moisture, but preferably 10% by weight or less, more preferably 5% by weight or less. If the water content of the sulfonate powder is 10% or more, the powder will dissolve and liquefy during heating and the water will evaporate, causing sulfonate crystals to adhere and solidify in the gap between the stirring blade and the wall surface. I don't like it because it is. The excess rate of caustic alkali is not limited to the method of alkali melting of the present invention, but it is usually 10 to 100%, preferably 20 to 80%, with as little water content as possible, and it is suitable for the method of the present invention. The most suitable one is in flake form.

The method of the present invention is carried out, for example, by the following method.

Powdered aromatic sulfonate is charged into an alkali melting reaction vessel, heated while stirring to reach a predetermined temperature, and then a caustic alkali is added at that temperature or while continuing to heat and raise the temperature, and after the addition is complete. , raise the temperature to the reaction completion temperature and keep it warm to complete the reaction. The rate of caustic addition must be adjusted so that the aromatic acid salt and the molten reactants remain in powder form at all times. If the addition is too early and the limit is exceeded, the viscosity will return to the high viscosity region or the content will become granular or solidified due to non-uniform dispersion and the reaction will not proceed smoothly. The temperature at which the caustic alkali is added is not limited, but is preferably 230°C or higher, preferably 250°C or higher. For example, even if the addition of caustic alkali is completed at a temperature below 230°C while the contents remain in a powder state, when the temperature begins to rise to complete the reaction, the reactant will pass from a muddy state to a high viscosity region. It may happen. The molten reaction product obtained in this way is treated by the usual treatment method.
For example, the aromatic oxy compound can be obtained by dissolving the reactant in water, neutralizing it with concentrated hydrochloric acid, extraction with an appropriate solvent, concentration, distillation, or acid precipitation and filtration.

According to the method of the present invention, the reaction can be carried out in a powder state throughout, so there is no need for particularly strong stirring power, addition of a third substance for the purpose of reducing the viscosity of the contents, or a large excess of caustic alkali. In addition, since there is little moisture in the contents, there is no adhesion to the wall surface, which is a problem when handling such powders and crystals, and a normal stirring blade is sufficient, so special attention should be paid to the gap between the material and the wall surface. There's no need. Also, there is no need to pay particular attention to the number of times of stirring, but it is a matter of course for those skilled in the art to insert a baffle plate or the like into the reactor from time to time in order to improve the stirring effect. It's not the main idea. Next, the present invention will be explained with reference to Examples, but the present invention is not limited thereto.

Example 1 300 with thermometer, stirrer, addition port, and reaction water distillation port
Powder 104y of trisodium 5-sulfoisophthalate containing 10% water was charged into a m1 cast steel alkaline melting pot,
The temperature was raised to 250°C, and flake caustic soda 447 was added while being careful to keep the contents in powder form. After the addition was completed, the temperature was raised to 30°C and kept at the same temperature for 2 hours to complete the reaction. .

The contents were powder-like throughout and did not adhere to the walls. The reaction product was dissolved in water and neutralized with hydrochloric acid, and the precipitated 5-oxyisophthalic acid was separated (▲), washed with water, and then dried. The yield based on trisodium 5-sulfoisophthalate was 90%.

Example 2 Powder 1137 of disodium biphenyl-4,4'-disulfonate containing 5% water was charged into the reaction vessel used in Example 1, and the temperature was raised from 230°C to 370°C. 98f of flaked caustic soda was added while keeping the contents a powder at all times.

After the addition, the mixture was kept at 370°C for 3 hours. During this period, the contents remained powdery throughout. The reaction product was dissolved in water, neutralized with dilute sulfuric acid, and the white crystals of 4.4/-dioxybiphenyl were separated, thoroughly washed with water, and dried. The yield is biphenyl-4
- It was 83% compared to 4-unit disulfonic acid disodium. Example 3 Powder of benzene-1,3-disulfonic acid disodium 1157 containing 2% water was charged into the same reaction vessel as used in Example 1, and 78.4y of flaked caustic soda was heated from 270°C to 340°C. The mixture was added while heating so that the contents always remained in powder form, and after the addition, the mixture was kept at 340° C. for 30 minutes to complete the reaction.

The reaction product in the form of a powder was cooled, dissolved in water, neutralized with concentrated hydrochloric acid, extracted with isopropyl ether, concentrated, and distilled. The yield of resorcin was 91%. Example 4 Powder 114y of benzene-1-carboxy-3,5-disulfonic acid trisodium containing 8% water was charged into the pot used in Example 1, and the temperature was raised to 230°C until the contents of the powdered caustic potassium 987 were dissolved. The mixture was added so as to maintain the powder throughout, and after the addition was completed, the temperature was gradually raised to 255°C and kept at the same temperature for 4 hours to complete the reaction.

The reaction product in powder form was dissolved in water, made strongly acidic with hydrochloric acid, extracted with isobutylone, concentrated until it became a crab-like substance, left to cool, and filtered to obtain the yield of 3,5-dioxybenzoic acid. is 77
It was %. Example 5 Powder of naphthalene-1,5-disulfonic acid disodium 1107 containing 10% water was charged into the same pot used in Example 1, and the temperature was raised, and 73.5 y of flaked caustic soda was added to 250
The contents were added while raising the temperature from 0.degree. C. to 285.degree. C. so that the contents always remained in powder form, and the reaction was completed by keeping the temperature at 285.degree. C. for 1 hour.

The contents were in powder form from beginning to end, and after the reaction was completed, it was neutralized with dilute sulfuric acid, and the precipitated crystals of 1,5-dioxynaphthalene were collected door to door.
After washing with water, it was dried under reduced pressure. The yield based on disodium naphthalene 1,5-disulfonate was 91%.

Claims (1)

[Claims] 1. When an aromatic sulfonate whose alkali-melted reaction product is essentially in the form of a powder is melted with an alkali to obtain the corresponding aromatic oxy compound, the molten reaction product remains in the powder state from beginning to end in the powdered aromatic sulfonate. 1. A method for alkali melting aromatic sulfonates, characterized in that caustic alkali is added at a rate such that the temperature is maintained.