JPS60217267A - Crystal modification of 3-dibutylamino-6-methyl-7-(4'- fluoroanilino)fluorane - Google Patents

Abstract

NEW MATERIAL:A crystal modification of the titled compound characterized by an X-ray diffraction showing the following peaks at the following diffraction angles (2theta): Strong peaks at 6.9 deg. and 19.1 deg. and peaks of medium intensity at 11.1 deg., 17.5 deg., 18.5 deg., 18.7 deg., 22.3 deg., 22.8 deg. and 23.9 deg.. USE:A color former for pressure-sensitive and thermographic recording methods, etc. having very little self coloring and yellowing property of the ground by sunlight with time. PREPARATION:2-(4'-Dibutylamino-2'-hydroxybenzoyl)benzoic acid is reacted with 4-fluoro-4-methoxy-2-methyl-diphenylamine in the presence of sulfuric acid at 0- 30 deg.C, and the reaction solution is then poured into ice water and cyclized in a mixed solution of an aqueous solution of an alkali and an organic solvent under heating. The organic solvent layer is then concentrated to give the alpha-modification, which is then treated in chlorinated benzene at 90-120 deg.C for 1-2hr to afford the beta-modification.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides 3-dibutylamino-6-methyl-7-(4-
Concerning the crystal modification of fluoroanilino)fluorane. More specifically, Cu-3-dibutylamino-6-methyl-7-(4-fluoroanilino ) This relates to the crystal modification of fluorane (hereinafter referred to as β-type modification).

Conventionally, pressure-sensitive copying uses a color reaction that occurs when an electron-donating colorless dye (color former) and an electron-accepting substance (color developer) are brought into contact with each other using physical force or heat to produce a colored image. The method or thermal recording method is well known and the three methods covered in this invention are
Among them, -dibutylamino-6-methyl-7-(4-fluoroanilino)fluoran is used as a coloring agent. The coloring agent for pressure-sensitive copying or heat-sensitive recording is required to have excellent coloring characteristics such as coloring sensitivity, coloring density, background coloring property, and various fastnesses after coloring, and it satisfies all of these properties. There are few coloring agents.

For example, when 3-dibutylamino-6-methyl-7-(4-fluoroanilino)fluorane is used as a coloring agent for heat-sensitive recording in a normally available crystalline form, it exhibits the above-mentioned coloring properties, especially self-coloring. The results were not completely satisfactory in terms of yellowing and yellowing over time.

The inventors have determined that 3-dibutylamino-6-methyroof-
As a result of intensive investigation into the relationship between the crystal form of (4-fluoroanilino)fluorane, the coloring properties of heat-sensitive recording materials using it, and yellowing over time, we discovered that this compound has two types of crystal modifications. Ta. In other words, it is a pale pink crystal, and when used as a coloring agent for heat-sensitive recording, it has excellent coloring sensitivity and various fastnesses of colored images, but has the drawbacks of self-coloring and severe yellowing of the skin over time due to sunlight. (hereinafter referred to as α-type transformation), it exhibits a white-pink color, and the coloring sensitivity and color fastness of the color images are the same as the α-type transformation, but the self-coloring property and the yellowing of the skin due to sunlight over time. There are two types of crystals with very little modification (β-type modification).

3-Dibutylamino-6-methyl-7-(4-fluoroanilino)fluoran is produced according to a conventional method, for example, as follows. That is, 2-(4-dibutylamino-
2-Hydroxybenzoyl)benzoic acid and 4-fluoro-
4-methoxy-2-methyl-diphenylamine in the presence of sulfuric acid (dehydration condensation agent) at -10 to 150°C, preferably 0
The reaction is carried out at ~30°C for several hours to several tens of hours. Next, the reaction solution was poured into ice water, and the resulting precipitate was separated as necessary, and then heated at 80-85°C 1-3 in a mixture of an aqueous alkaline solution such as caustic potash or caustic soda and an organic solvent such as toluene.
The ring is closed by heating for a period of time. Next, the reaction solution is allowed to stand, and after separation, the organic solvent layer is concentrated, and methanol or ethanol is added to the concentrated solution to precipitate crystals, thereby changing the α-type modification.

Such α-type transformation is carried out using 2 to 10 times the amount of chlorinated benzene such as monochlorobenzene, dichlorobenzene, trichlorobenzene, etc. at 70 to 150°C for 30 minutes to 3 hours, more preferably at 90°C to 120°C for 1 to 2 hours. β-type metamorphosis is obtained by time treatment.

In addition, after removing phthalide, which is an intermediate product in the synthesis of 3-butylamino-6-methyl-,7-(4'-fluoroanilino)fluorane, the ring is closed with the above-mentioned mixture of chlorinated benzene and aqueous caustic alkali solution. After that, separate the liquids and 3-
The β-type modification can also be achieved by treating a chlorinated benzene solution containing butylamino-6-methyl-7-(4-fluoroanilino)fluorane at the temperature and time described above.

Next, 3-dibutylamino-6-methyl-7-(4--y
The α-type modification and β-type modification of fluorane (fluoroanilino) will be explained with reference to the drawings. Figures 1 and 2 show powder
It is based on a line diffraction method, and is a diagram in which the diffraction state of α rays on Cu- is recorded using a proportional counter. Figure 1 shows the β-type transformation, and the diffraction angle (2θ
) shows strong peaks at 6.9 and 19.1°, and an intense peak at 11.1°. FIG. 2 shows the α-type crystal, showing strong peaks at diffraction angles (2θ) of 11.8 and 20.7, and other peaks clearly different from those of the α-type crystal.

=5= (An error of about 0.2° is allowed in the display of the diffraction angle) And whether or not the α-type transformation is converted to the β-type transformation of the present invention in the above treatment method can be determined by X-ray diffraction. It is determined by measuring the figure, but a simpler method of identification is also by measuring the melting point of the sample. That is, α-type metamorphosis is m, p, 135-1
37°C, whereas the β-type transformation is m, p, 169~
It shows 171°C.

Next, the present invention will be specifically explained with reference to Examples and comparative tests. (In Examples and Comparative Tests, parts indicate parts by weight) Reference Example 3 Synthesis of 3-butylamino-6-methyl-7-(4'-fluoroanilino)fluoran 2-(4-dibutylamino-2-hydroxy 36.9 parts of benzoyl)benzoic acid, 4-fluoro-4-methoxy-
23.1 parts of 2-methyl-diphenylamine was added to 20 parts of concentrated sulfuric acid.
After reacting at 0 to 5°C for 20 hours, the resulting crystals 6- were filtered and washed with water 11 to form a phthalide cake (3-(4-
dibutylamino-2-hydroxyphenyl)-3-[5
-(p-fluoroanilino)-2-methoxy-4-methylphenyl]phthalide).

This phthalide cake was mixed with 200ml of monochlorobenzene,
After adding to a mixed solution consisting of 100 ml of water and neutralizing with 28% caustic soda, 4 parts of caustic soda are added and stirred at 80 to 85°C for 3 hours. After standing still, separate the monochlorobenzene layer,
While maintaining the temperature above 70°C, the mixture was concentrated until a syrup-like substance was obtained, and then 300 ml of methanol was added to precipitate crystals.
41 parts of α-modified dibutylamino-6-methyl-7-(4-fluoroanilino)fluorane were obtained. (mp-13
5-1378C) Example 1゜The α-modified 3-dibutylamino-6-methyl-7
100 ml of 0-dichlorobenzene was added to 41 parts of -(4-fluoroanilino)fluorane and treated at 100 to 110°C for 1 hour to obtain 38 parts of a milky white β-type modified product. This gave an X-ray diffraction pattern as shown in FIG. (m
p=169-171°C) Example 2 A phthalide cake obtained in the same manner as in the above reference example was mixed with 20% of monochlorobenzene. O, ml water 10
After neutralizing with 28% caustic soda, 4 parts of caustic soda is added and stirred at 80 to 85°C for 3 hours. After standing still, the liquid was separated and monochlorobenzene was added under reduced pressure.10. After distilling off Oml, 3-butylamino-6-
Monochlorobenzene containing methyl-7-(4-fluoroanilino)fluorane was treated at 110 to 120°C for 90 minutes to produce a white-pink 3-modified β-type, which shows the X-ray diffraction pattern in Figure 1.
40 parts of butylamino-6-methyl-7-(4-fluoroanilino)fluorane were obtained. (mp=169~171
°C) Comparative Test 3 The following comparative test was conducted to compare the effects of α-type and β-type modifications of dibutylamino-6-methyl-7-(4-fluoroanilino)fluorane on thermal recording paper. did.

CA) Liquid α- or β-modified 3-dibutylamino-
6-Methyl-7-(4-fluoroanilino)fluorane 15.0 parts Gose/-L GL-05H (25% aqueous solution) (Nippon Gosei) 12.0 parts Water 33.0 parts [B) Liquid Bisphenol A 34.5 parts Gohsenol GL-0.5H (25% aqueous solution) 20.0 parts Water 11
0.0 part (A), CB) Both liquids were separately ground and dispersed using a sand grinder and a sander so that the average particle size was 1 to 3μ, and the parts for liquids (A) and [B] were A dispersion was prepared.

Further, a mixture consisting of the following composition was ground and dispersed using a sand grinder for 2 hours to prepare a dispersion of liquid [C].

(C) Liquid Aramide HT-P (manufactured by Lion Akzo)
29.5 parts Calcium carbonate 60.0 parts Gohsenol GL-05H (25% aqueous solution) 20.0
Part water 109.0 parts Dispersion of liquid (A): Dispersion of liquid [B]: [C] 9
- Prepare a heat-sensitive coloring layer forming liquid by mixing the liquid dispersion in a ratio of 6:47:47, and apply it to the surface of high-quality paper with a basis weight of about 501/- so that the dry solid content is 5 P/-, Dried, α-modified and β-modified 3-dibutylamino-6-methyl-7-
A thermal recording paper containing (4-fluoroanilino)fluorane was obtained.

The following table shows the results of a comparative test using thermosensitive recording paper of α-type transformation and β-type transformation.

0 background color density: Measured with a Macbeth densitometer RD-914.

0 Yellowing property: The thermal recording paper was left near a window for 98 hours, and the degree of yellowing of the background color of the thermal recording paper was examined.

○: Good ×: Bad

[Brief explanation of drawings]

Figures 1 and 2 are X-ray diffraction patterns of the β-type modification and the α-type modification of 3-dibutylamino-10-6-methyl-7-(4-fluoroanilino)fluorane. In the drawings, the horizontal axis represents the diffraction angle (2θ), and the vertical axis represents the diffraction intensity. Patent applicant Nippon Kayaku Co., Ltd. 11-

Claims (1)

[Claims] (,1) Strong peaks at diffraction angles (2θ) of 6.9° and 19.1° in X-ray diffraction using Cu-Kα rays, 1
1.1, 17.5, 18.5.18.7, 22.3, 2
Crystal modification of 3-dibutylamino-6-methyl-7-(4-fluoroanilino)fluorane characterized by an X-ray diffraction diagram showing intermediate intensity peaks at 2.8 and 23.9.