JPS60255791A - Fluoran compound and its preparation - Google Patents

Abstract

NEW MATERIAL:A compound shown by the formula I (R is 2-propenyl; X and Y are H, Cl, or methyl). EXAMPLE:2-Anilino-3-methyl-6-(N-di2'-propenylamino)-fluoran. USE:A black coupler for heat-sensitive-, pressure-sensitive recording paper, etc. Having improved self-coloring properties and fastness, especially suitable for high-speed facsimile. PREPARATION:A compound [e.g., 2-(4-N-di2'-propenylamino-2-hydroxybenzoyl) benzoic acid, etc.] shown by the formula II is condensed with a compound (e.g., 2-methyl-4-methoxy-diphenylamine, etc.) shown by the formula III (R' is H, or 1- 4C alkyl) by the use of a condensation agent (preferably sulfuric acid with 85- 100wt% concentration).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel fluoran compound and a method for producing the same.

More specifically, the present invention is a fluoran compound represented by the general formula (1) (wherein R represents a 2-propenyl group, and X and Y represent hydrogen, chlorine, or methyl groups) and a method for producing the same.

The fluoran compound represented by the general formula (1) of the present invention is a novel compound that has not yet been described in the literature.

Heat-sensitive recording paper, current-carrying heat-sensitive recording paper, and pressure-sensitive paper that utilizes a color-forming reaction caused by contact between an almost uncolored electron-donating substance (color former) and an almost uncolored electron-accepting substance (color developer). Demand for recording paper is increasing with the development of the current information age. Among the coloring agents used in these recording papers, progress has been made in developing dyes that produce black images in particular, but a single black coloring agent still has problems in hue, self-coloring (background fog), and fastness. At present, no one has been found that is satisfactory in all respects, including cost and cost. Furthermore, recently there has been an increasing demand for faster speeds in facsimile machines that use thermal recording paper, and there are high expectations for color formers that can produce clear black images at high speeds.

Currently, black coloring agents for heat-sensitive recording paper and pressure-sensitive recording paper include, for example, 2-anilino-3-methyl-6-dinithylaminofluorane, 2-anilino-3-methyl-6-
(N-methyl-cyclohexylamino)-fluorane,
A typical example is 2-anilino-3-methyl-6-(N-ethyl-p-toluidino)-fluoran, but these coloring agents do not have sufficient performance especially for use in high-speed facsimiles.

The present inventor has discovered that the fluorane derivative represented by the general formula (1) is itself a colorless white crystal, but when brought into close contact with an electron-accepting substance, it develops a black tone and exhibits light resistance and water resistance. When applied to heat-sensitive recording paper or pressure-sensitive recording paper, it has excellent self-coloring properties and fastness, and is a useful pigment particularly suitable for high-speed facsimile. I discovered something.

The fluoran compound of the present invention can be produced, for example, as follows.

A compound represented by the general formula (n) (wherein R has the above meaning) and a compound represented by the general formula (In) (wherein R' represents hydrogen or an alkyl group having 1 to 4 carbon atoms, and , Y has the above-mentioned meaning) in the presence of a condensing agent at -5 to 90° C. for several hours to several tens of hours.

Next, the precipitate formed by pouring into water is filtered, and the cake is heated in an alkaline aqueous solution to obtain slightly colored white crystals. When this is filtered, dried, and recrystallized, a fluoran compound represented by the general formula (+) is obtained as white crystals.

Here, the compound represented by the general formula (n) and the general formula (I
As the condensing agent used when synthesizing the compound of general formula (1) from the compound of II), sulfuric acid, phosphoric acid, polyphosphoric acid, etc. are used, but 85% to 100% concentration of sulfuric acid is advantageously used. . Further, during this condensation reaction, solvents such as halogenated aliphatic hydrocarbons, halogenated aromatic hydrocarbons, acetic acid, and dioxane may be used, and these solvents may be removed at an appropriate time during the synthesis.

After the condensation reaction, the fluoran compound can be separated from the alkaline aqueous solution by filtration as described above, or by extraction using an organic solvent that is immiscible with the water added during the alkali treatment.

The purity of the fluoran compound treated with alkali by such a method can be further increased by recrystallization. Examples of the recrystallization solvent include orthodichlorobenzene, anisole, 1,2,4-trimethylbenzene, orthoxylene, isopropylbenzene, diisopropylbenzene, paracymene, 2-ethylhexanol, cyclohexanol, benzyl alcohol, furfuryl alcohol, Ethylene glycol, 2-butoxyshetanol, decane, dimethylformamide, toluene, chlorobenzene, methyl isobutyl ketone, isobutanol,
Isopropanol, n-hexane, etc. are used.

One or more color formers obtained in this way are
Heat-sensitive or pressure-sensitive recording paper can be produced by a conventional method using the dye or in combination with other color formers. Examples of color developers commonly used at this time include bisphenol A
, bisphenols such as cyclohexylidene bisphenol, phenylphenol, alkylphenols,
Esters of oxybenzoic acid such as benzyl P-oxybenzoic acid ester, formalin novolac resins of phenol and alkylphenol, sulfur chloride condensates of alkylphenol, zinc or calcium salts of salicylic acid and its derivatives, activated clays, clays, aromatics Examples include carboxylic acids, sulfonic acids, and metal salts thereof.

In addition to the glue, light stabilizer, and lubricant normally used in the production of recording paper, there is also a flux in thermal paper.

It is generally well known that a capsule material and a capsule solvent are used in pressure-sensitive paper.

Next, the present invention will be explained in more detail with reference to Examples.
The starting material, 2-(4-N-di2'-propenylamino-2-hydroxybenzoyl)benzoic acid, is obtained by dialkylating mono-aminophenol with 2-propenyl chloride or 2-propenyl bromide, and then with phthalic anhydride. Synthesized by condensation.

Example 1 2-(4-N-di2'-propenylamino-2-hydroxybenzoyl)benzoic acid (melting point 1) was added to 15 g of 96% sulfuric acid.
27~128"C) 3.37g, then 10~128"C)
2.14 g of 2-methyl-4-methoxy-diphenylamine was dissolved at 15°C and stirred at the same temperature for 24 hours. After pouring into 80 g of ice water, the precipitate was filtered and washed with water. The cake was placed in 80 cc of water, made strongly alkaline with caustic soda, and 20 g of toluene was added, followed by stirring at 80° C. for 2 hours.

Toluene is distilled off, filtered, washed with water, and dried. Dry product 4.
6g was recrystallized from isopropanol to give a melting point of 157~
3.50 g of 2-anilino-3-methyl-6-(N-di2'-propenylamino)-fluoran was obtained as white crystals at 158°C. It develops a black color due to silica gel and bisphenol.

Example 2 2-(11-N-di2'-propenylamino-2-hydroxybenzoyl)benzoic acid 3.
Then, 2.13 g of 2,4'-dimethyl-4-hydroxy-diphenylamine was dissolved at 10-15 DEG C. and stirred at the same temperature for 24 hours. Thereafter, it was treated in the same manner as in Example 1, recrystallized from isopropanol, and the melting point was 1.
2-(4'-methylanilino)-3- at 80-182°C
2.60 g of methyl-6-(N-di2'-propenylamino)-fluorane was obtained as white crystals. Silica gel produces a black color, and bisphenol A produces a green-black color.

Example 3 3.37 g of 2-(4-N-di2'-propenylamino-2-hydroxybenzoyl)benzoic acid in 15 g of 96% sulfuric acid
Dissolve g.

Next, 1.99 g of 4-methoxy-diphenylamine was dissolved at 10-15 DEG C. and stirred at the same temperature for 24 hours. Pour into 80 cC of ice water, filter the precipitate, wash with water and dry.

This was heated with 5 g of ethylene glycol, diluted with isopropanol tog, cooled, filtered, washed with inpropanol and water, and dried. Melting point '186.5~】87°5
2.9 g of 2-anilino-6-(N-di2'-propenylamino)-fluorane was obtained as white crystals. Silica gel produces a black border color, and bisphenol A produces a dark green color.

Example 4 Instead of 4-methoxydiphenylamine in Example 3, 4-methoxy-2'-chloro-diphenylamine 2
．． After carrying out the same operation using 34 g, the sulfuric acid solution was poured into 80 cc of ice water, and the precipitate was filtered, washed with water, and dried.

After heating this with 5g of ethylene glycol, 20cc of water
was added, boiled, cooled, filtered, washed with water, and dried. This was recrystallized from 90% isopropanol with a melting point of 146~
2-(2'-chloroanilino)-6-(N-
3.2 g of di2'-propenylamino)-fluorane were obtained as white crystals. Silica gel produces a purple-black color, and bisphenol A produces a black color.

Example 5 The same procedure as in Example 1 was carried out except that 2.34 g of 2-chloro-4-methoxydiphenylamine was used instead of 2-methyl-4-methoxydiphenylamine.

The precipitate obtained by pouring the sulfuric acid solution into ice water was treated with an aqueous caustic soda solution and toluene at 80° C. for 2 hours, and then the toluene layer was separated and the toluene was distilled off.

A viscous substance obtained by recrystallizing this from isopropanol crystallizes when boiled with water. When filtered, washed with water, and dried, 2-anilino-3-chloro-6-(N-di2''-propenylamino) is obtained as almost uncolored crystals.
- Obtained a fluoran sword. The melting point is 76-78°C. Silica gel produces a black color, and bisphenol 8 produces a greenish black color.

Example 6 The same procedure was repeated using 2.48 g of 2-methyl-4-methoxy-4'-chloro-diphenylamine in place of 4-methoxydiphenylamine in Example 3, and recrystallization was performed from Impropatol. 2 with a melting point of 160-162℃
-(4'-chloroanilino)-3-methyl-6-(N-
3.7 g of di2'=propenylamino)-fluorane were obtained as white crystals. Silica gel produces a purple-black color, and bisphenol A produces a black color.

Patent applicant: Taoka Chemical Industry Co., Ltd.

Claims (2)

[Claims] (1) A fluoran compound represented by the general formula (1) (wherein R represents a 2-propenyl group, and X and Y represent hydrogen, chlorine, or methyl group). (2) A compound represented by the general formula (II) (wherein R represents a 2-propenyl group) is converted into a compound represented by the general formula (III) (wherein R' is hydrogen or an alkyl group having 1 to 4 carbon atoms). is condensed with a compound represented by the formula (X, Y represents hydrogen, chlorine or methyl group).
1) A method for producing a fluoran compound represented by the formula (wherein R, X, and Y have the above-mentioned meanings).