JPH05255234A - Production of diphenylsulfone compound - Google Patents

Abstract

PURPOSE:To obtain in high yield with low level of concomitant by-products a 4-alkoxy-4'-hydroxydiphenylsulfone useful at a developer for heat-sensitive recording materials. CONSTITUTION:An alkyl halide is added to a two-phase solvent system composed of (A) an aqueous alkaline matter solution with 4,4'- dihydroxydiphenylsulfone dissolved therein and (B) an organic solvent immiscible with water followed by addition of an alkaline substance to maintain the pH value of the system, thus affording the objective 4,4'-dihydroxydiphenylsulfone. Besides, there are several characteristics in this method; namely: (l) 1.2-1.8mol, per mol of the 4,4'-dihydroxydiphenylsulfone, of the alkyl halide is added, followed by reaction for >=4hr and then further addition of 0.2-0.6mol of the alkyl halide; (2) the latter alkyl halide addition (at 0.2-0.6mol) is made either in several portions or in a continuous way; and (3) the organic solvent immiscible with water is toluene.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing 4-alkoxy-4'-hydroxydiphenyl sulfone which is useful as a developer for heat-sensitive recording materials.

[0002]

4-Alkoxy-4'-as a color developer
Hydroxydiphenyl sulfone is more widely used as a recording material for high-speed recording such as a facsimile or a label with an emphasis on storability because it is superior in color development sensitivity, storability, and light resistance to conventional color developers. There is. This 4-alkoxy-4'-hydroxydiphenyl sulfone is disclosed in JP-A-58-20493 and JP-A-58-82788.
JP-A-60-13852 and the like are disclosed as being excellent as a color developer for heat-sensitive recording paper. On the other hand, as for the production method, the method characterized in that the production is performed in a water solvent in the presence of 1.5 to 3.0 times mole of alkali is disclosed in International Publication W.
O91 / 11433 and the product is 4-benzyloxy-4'-hydroxydiphenyl sulfone, which is different from the compound of the present invention, but the amount of benzyl chloride as a raw material and the amount of alkaline compound used are noted. A manufacturing method is disclosed in JP-A-59-225157. In any of the production methods, attention is paid to the amount of the alkaline substance used to improve the suppression of the production of the by-product disubstituted diphenylsulfone and the improvement of the yield, but it cannot be said to be sufficient.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems, and 4-alkoxy-4'- by a simpler reaction process.
It is intended to provide a method for selectively producing hydroxydiphenyl sulfone.

[0004]

The present invention provides a method for producing 4-alkoxy-4'-hydroxydiphenylsulfone by reacting 4,4'-dihydroxydiphenylsulfone with an alkyl halide. To maintain the pH at 7.5 to 9.5 by adding an alkyl halide to a two-phase solvent system including an aqueous solution of an alkaline substance in which diphenyl sulfone is dissolved and a non-water-miscible organic solvent, and adding an alkaline substance. It is a method for producing 4-alkoxy-4′-hydroxydiphenyl sulfone, which is characterized. Further, a method of adding 1.2 to 1.8 mol of an alkyl halide to 4 mol of 4,4′-dihydroxydiphenyl sulfone and reacting for 4 hours or more, and further adding 0.2 to 0.6 mol of an alkyl halide. , 0.2 to 0.6 mol ratio of alkyl halide is added in several times or continuously, and an aqueous solution of an alkaline substance is added in several times or continuously to adjust pH to 7.5 to 9.5. The method of holding and the method of using toluene as a non-water-miscible organic solvent.

The production method of the present invention is represented by a reaction formula. (In the formula, R represents an alkyl group having 1 to 10 carbon atoms, and X represents a halogen atom), where the general formula (I) is 4-alkoxy-4′-hydroxydiphenyl sulfone, and the formula (II) is Represents 4,4′-dihydroxydiphenyl sulfone, and the general formula (III) represents an alkyl halide.

The method of the present invention will be described in detail. There are various methods for preparing the two-phase solvent system, and it is possible to produce them in various orders, but the alkaline substance is 1.0 to 2.0 mol ratio, preferably 1.3 to 1.8 mol ratio. It is convenient to heat-dissolve 1.0 mol ratio of 4,4′-dihydroxydiphenyl sulfone in an aqueous solution in which is dissolved, and further add a non-water-miscible organic solvent to form a two-phase solvent system. When an alkyl halide is added thereto and reacted, first, 1.2 to 1.8 mole ratio of the alkyl halide is added to proceed the reaction. It takes at least 4 hours for the reaction to proceed to such an extent that the reaction of the added alkyl halide is substantially completed, but 5 to 10 hours is usually sufficient. During this time, the pH is 7.5
9.5 is retained. Further, alkyl halide 0.2 to 0.
The reaction is completed by adding 6 moles in several portions or continuously. During this reaction, an alkaline substance is added to maintain the pH of the reaction solution at 7.5 to 9.5. The alkaline substance is easy to handle when added as an aqueous solution. After the reaction was completed, the aqueous layer was separated, and the organic solvent layer was cooled and crystallized to obtain 4
Separate the alkoxy-4'-hydroxydiphenyl sulfone. The total amount of alkyl halide used is 1.4-2.
A 2 molar ratio is preferred. If it is 1.4 mol% or less, the yield cannot be improved, and if it is 2.2 mol% or more, the economic effect becomes poor. As a method for maintaining the pH of the reaction solution, the range of this pH is intermittently adjusted and the interval may be raised or lowered according to the progress of the reaction, or continuously adjusted to reduce the fluctuation range. Good.

When 4,4'-dihydroxydiphenyl sulfone is dissolved in an alkaline substance, the pH is 9.0 to 9.
It is 5. When the first alkyl halide is added to the solution and the reaction proceeds, the alkyl halide is consumed not only by the reaction but also by hydrolysis, and the hydrogen halide generated at that time consumes the alkaline substance in the system, lowering the pH. , PH
When it is less than 7.5, the reaction hardly progresses. Therefore, it is preferable to add and replenish the alkyl halide before the pH reaches 8.0 or less. As a method of adding and replenishing the alkyl halide, there are a method of intermittently adding in several times and a method of continuously pouring. It is also necessary to consider the method of adjusting the pH with an alkaline substance depending on the addition method. In the former case, it is preferable to keep the pH within the range of 7.5 to 9.5 by intermittently adding an aqueous solution of an alkaline substance corresponding to the addition amount of alkyl halide, and in the latter case, the pH is constantly monitored. It is preferable to adjust continuously to reduce the fluctuation range. That is, not only the amount of the alkyl halide used with respect to 4,4′-dihydroxydiphenyl sulfone in the reaction system but also the amount of the alkaline substance present in the reaction system is important. When the amount of the alkaline substance present is large (pH 9.5 or higher), the amount of the by-product di-substituted diphenyl sulfone is increased, and the alkyl halide as a raw material is often decomposed. On the contrary, when the amount is small (pH 7.5 or less), the reaction progresses extremely slowly.

In the above reaction, the amounts of water and the water-immiscible organic solvent used are also important, and water is 500 with respect to 1.0 mol ratio of 4,4'-dihydroxydiphenyl sulfone.
˜1500 ml, preferably 800 to 1200 ml, which is the minimum amount of 4,4′-dihydroxydiphenylsulfone to be dissolved as a sodium salt when heated, and the non-water-miscible organic solvent is 4,4′-dihydroxydiphenylsulfone 1. 500 to 1500 ml, preferably a minimum amount of 800 to 12 that dissolves the 4-alkoxy-4'-hydroxydiphenyl sulfones formed with respect to 0.0 mol ratio when heated.
It is 00 ml.

The reaction temperature can be arbitrarily selected from room temperature to the reflux temperature of water or a non-water-miscible organic solvent, but the reflux temperature is preferred from the viewpoint of reaction rate. When an alkyl halide having a low boiling point is used, when an appropriate amount of an organic solvent having a higher boiling point is used, the reaction can be performed at a temperature higher than the boiling point of the alkyl halide, which is effective in increasing the reaction rate and the reaction rate. ..

Examples of the non-water-miscible organic solvent used in the present invention include aromatic solvents such as toluene, xylene and chlorobenzene, and aliphatic solvents such as methyl isobutyl ketone. Examples of the alkaline substance include hydroxides of alkali metals and / or alkaline earth metals or salts thereof. Examples thereof include sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, magnesium hydroxide, sodium carbonate and the like, and sodium hydroxide is preferable. The alkaline substance aqueous solution is a liquid obtained by dissolving these alkaline substances in water at an arbitrary concentration.

The present invention will be described in detail below with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Example 1 12.8 g (0.32) of sodium hydroxide was added to 190 ml of water.
50.0 g (0.20 mol) of 4,4′-dihydroxydiphenyl sulfone was further added and dissolved by heating. The pH was 9.2. And toluene 16
8 ml was added and the mixture was stirred to obtain a two-phase solvent system. Further, 39.4 g (0.32 mol) of isopropyl bromide was added and reacted at 80 ° C. for 6 hours. At this time, the pH was 8.3. Next, a 20% aqueous solution containing 1.6 g (0.040 mol) of sodium hydroxide and 4.9 g of isopropyl bromide (0.0
40 mol) was added, and the reaction was further performed at 80 ° C. for 8 hours. p
H was 8.2. 0.6 g of sodium hydroxide
A 20% aqueous solution containing (0.015 mol) and 6.0 g (0.049 mol) of isopropyl bromide were added, and the mixture was heated under reflux (80 ° C.) and reacted for 10 hours. The pH was 8.0. During this time, the pH went up and down between 9.2 and 8.0. After reacting for a total of 24 hours, 106 ml of toluene was added and the pH was adjusted to about 8.degree.
The liquid was adjusted to 5 and allowed to stand for liquid separation. Toluene 143 in the toluene layer
ml and warm water (108 ml) were added and the mixture was washed and then left standing to perform liquid separation. The components of this toluene layer were measured by liquid chromatography.
78% of 4'-hydroxydiphenyl sulfone,
The by-product 4,4'-diisopropoxydiphenyl sulfone was 5%, and the production rate of the by-product was small. Further, the toluene layer was cooled to precipitate crystals, and 4-isopropoxy-4′-hydroxydiphenyl sulfone, melting point 12
42.5 g of white crystals having a temperature of 9 to 131 ° C. were obtained. The purity measured by liquid chromatography was 99.0%.
However, it contained almost no by-products, and the yield from 4,4′-dihydroxydiphenyl sulfone was as high as 72%.

Comparative Example 1 In Example 1, 190 ml of water was added to 1 ml of sodium hydroxide.
Dissolve 2.8 g (0.32 mol) and add 4,4'-
Dihydroxydiphenyl sulfone 50.0 g (0.20
Mol) was added and dissolved by heating, and 168 ml of toluene was added. Isopropyl bromide 50.3 g (0.409 mol) and sodium hydroxide 2.2 g (0.055 mol)
A 20% aqueous solution containing ## STR3 ## was added all at once without reaction and reacted. During this time, the pH had dropped from 9.6 to 7.2.
When the components of the toluene layer were measured in the same manner as in Example 1,
The production rate of each is 4-isopropoxy-
4'-hydroxydiphenyl sulfone is 69%,
The content of 4,4'-diisopropoxydiphenyl sulfone as a by-product was 16%, and the production rate of the target compound was decreased and the by-product was increased. Then, similarly from the toluene layer,
There were obtained 37.2 g of 4-isopropoxy-4′-hydroxydiphenyl sulfone, a white crystal having a melting point of 129 to 131 ° C. When the purity was measured by liquid chromatography,
It was 99.0% and contained almost no by-products,
The yield from 4,4′-dihydroxydiphenyl sulfone was as low as 63%.

[0013]

INDUSTRIAL APPLICABILITY The present invention can suppress the production of by-product 4,4′-dialkoxydiphenylsulfone, and can obtain the objective compound 4-alkoxy-4′-hydroxydiphenylsulfone in a high yield. ..

Claims (4)

[Claims] 1. A 4-alkoxy-compound obtained by reacting 4,4′-dihydroxydiphenyl sulfone with an alkyl halide.
In the method for producing 4'-hydroxydiphenyl sulfone, an alkyl halide is added to a two-phase solvent system comprising an aqueous solution of an alkaline substance in which 4,4'-dihydroxydiphenyl sulfone is dissolved and a non-water-miscible organic solvent, and the alkaline substance is added. Is added to maintain the pH at 7.5 to 9.5, and a method for producing 4-alkoxy-4′-hydroxydiphenyl sulfone. 2. A mole ratio of alkyl halide of 1.2 to 1.8 is added to 1 mole of 4,4′-dihydroxydiphenyl sulfone, and the reaction is carried out for 4 hours or more. Further, a mole ratio of alkyl halide is 0.2 to 0.6. The method according to claim 1, wherein 3. An alkyl halide in an amount of 0.2 to 0.6 mol is dividedly or continuously added several times, and an aqueous solution of an alkaline substance is dividedly or continuously added several times to obtain pH.
The method according to claim 2, which is held at 7.5 to 9.5. 4. The method according to claim 1, wherein the water-immiscible organic solvent is toluene.