JP2784532B2 - Method for producing 3,3-bis- (4-dimethylaminophenyl) -6-dimethylaminophthalide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] 3,3-bis- (4-dimethylaminophenyl) -6-dimethylaminophthalide represented by the formula (2) is generally crystal violet lactone (hereinafter referred to as CVL). This CVL is widely used as a reactive dye in pressure-sensitive copying paper, heat-sensitive recording paper, and the like.

(In the formula, Me means CH ₃ ; the same applies hereinafter.) The present invention relates to an improved method for producing CVL.

[Conventional technology and problems to be solved by the present invention]

2- [4,4'-bis- (dimethylamino) -benzohydryl] -5-dimethylaminobenzoic acid (hereinafter referred to as LC) represented by the formula (1) is oxidized to obtain a CV represented by the formula (2).
Many production methods for synthesizing L are known.

However, in the conventional production method, the production process is complicated, and there are many decomposition by-products due to oxidation, and it is difficult to obtain high-quality CVL with high yield.

For example, LC in an organic solvent such as glacial acetic acid, chloroform,
A method of oxidizing oxygen in the presence of chloranil and a metal complex (JP-A-48-25730), and a method of oxidizing LC with hydrogen peroxide in a mixed solution of a water-insoluble hydrocarbon solvent and water (JP-A-48-25730) No. 52-78867), the recovery of the solvent was complicated and the yield was low. In the method of oxidizing LC with lead peroxide, potassium permanganate or the like in a mineral acid aqueous solution (U.S. Pat. No. 2417897), a large amount of by-products was formed, which caused a serious defect in quality. Also, a method of oxidizing LC with hydrogen peroxide in a basic aqueous solution or a water-soluble organic solvent (JP-A-52-31384),
Oxidation with hydrogen peroxide, oxygen or air in the presence of a catalyst of cobalt and copper compounds (Japanese Patent Publication No. 59-19548), hydrogen peroxide, oxygen or oxygen in the presence of a metal compound having an atomic weight of 50 to 56 In the method of oxidizing with an oxygen-containing gas (JP-A-58-38279), unreacted LC remains forever and the yield is not improved.

The present invention has been made in view of the above prior art,
The purpose of the present invention is to provide an improved production method capable of improving the yield and quality of CVL.

[Means for solving the problem]

As described above, the use of a metal catalyst for the oxidation reaction of LC is well known, but it has been difficult to select an appropriate catalyst, and satisfactory results have not been obtained.

The present inventors have conducted intensive studies to improve the drawbacks of the conventional LC oxidation method, and as a result, have found that the addition of a chelating agent to a specific metal catalyst exerts its catalytic effect more strongly. In particular, by adding a chelating agent to a mixed catalyst of iron and manganese compounds, the yield and quality of CVL can be further improved.

That is, in the present invention, in a basic aqueous solution in which the LC is adjusted to pH 7.0 to 14.0, the presence of three types of catalysts, iron, a manganese compound, and a chelating agent, is essential.
This is an improved method for producing CVL, comprising oxidizing using oxygen or an oxygen-containing gas.

In the present invention, specific examples of iron compounds in the catalyst used include ferrous chloride, ferrous sulfate, iron phthalocyanine and the like; manganese compounds such as manganese dioxide, manganese chloride and manganese sulfate; chelating agents such as tartaric acid; Examples of such compounds include compounds capable of chelating with iron and manganese, such as gluconic acid, ethylenediaminetetraacetic acid and the like, and sodium, potassium and amine salts thereof. In order to adjust the pH of the reaction aqueous solution to 7.0 to 14.0, a basic compound such as hydroxide or carbonate of sodium or potassium, or ammonia can be optionally used. Usually, the oxidation reaction is carried out at a temperature of 50 to 100 ° C., and is achieved by introducing hydrogen peroxide, oxygen or an oxygen-containing gas as an oxidizing agent into the reaction solution at atmospheric pressure or under pressure.

(Examples, etc.)

Next, with reference to Examples and Comparative Examples, it is clarified that the improved production method of the present invention improves the yield and quality of CVL.

Example 1 In an autoclave equipped with an air introduction tube, 41.7 g of LC, a catalyst (0.1 g of ferrous chloride, 0.1 g of manganese sulfate, 0.5 g of disodium ethylenediaminetetraacetic acid), 5.3 g of sodium carbonate, and 500 of water
cc was added. This was heated to 90 ° C., and air 10.7 was introduced over 4 hours while maintaining the gauge pressure of the reaction vessel at 2 kg / cm ² . The product was filtered off from the reaction solution, sufficiently washed with water and dried to obtain 41.3 g of pale yellow crystals (m.p. 182 to 184 ° C).

Example 2 The catalyst of Example 1 (ferrous chloride 0.1 g, manganese sulfate 0.1 g,
The procedure of Example 1 was repeated, except that ferrous sulfate (0.1 g), manganese sulfate (0.1 g), and sodium gluconate (0.5 g) were used instead of ethylenediaminetetraacetic acid disodium salt (0.5 g). 41.1 g (m.p. 181.5-183.5 ° C.) were obtained.

Comparative Example 1 The catalyst of Example 1 (0.1 g of ferrous chloride, 0.1 g of manganese sulfate,
The same operation as in Example 1 was carried out except that only ferrous chloride (0.1 g) was used instead of ethylenediaminetetraacetic acid disodium (0.5 g), but pale yellow-brown crystals (34.2 g, m.p.
° C).

Comparative Example 2 The catalyst of Example 1 (ferrous chloride 0.1 g, manganese sulfate 0.1 g,
Example 1 except that only 0.1 g of manganese sulfate was used instead of 0.5 g of ethylenediaminetetraacetic acid disodium salt).
The procedure was the same as described above, but 29.8 g of yellow-brown crystals (m.p. 175-177 ° C)
Was just obtained.

Comparative Example 3 The catalyst of Example 1 (ferrous chloride 0.1 g, manganese sulfate 0.1 g,
The procedure of Example 1 was repeated, except that ferrous chloride (0.1 g) and manganese sulfate (0.1 g) were used instead of ethylenediaminetetraacetic acid disodium (0.5 g), but 37.7 g of pale yellowish brown crystals were used.
(M.p. 179 DEG-181 DEG C.).

[Action and Effect of the Invention]

As described above, the present invention applies the effect of activating a chelating agent to the CVL production method in addition to the effect of mixing a specific catalyst. As a result, high-quality CVL that cannot be obtained by the conventional method can be obtained in high yield.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-62-184061 (JP, A) JP-A-55-2496 (JP, A) JP-A-50-124931 (JP, A) JP-A 47-49 10632 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) C09B 11/00 CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] (1) 2- [4,4'-bis- (dimethylamino)-represented by
Benzohydryl) -5-dimethylaminobenzoic acid at pH 7.
Oxidation using hydrogen peroxide, oxygen or an oxygen-containing gas in a basic aqueous solution adjusted to 0 to 14.0 in the presence of three types of catalysts, iron, manganese compounds and chelating agents A method for producing 3,3-bis- (4-dimethylaminophenyl) -6-dimethylaminophthalide represented by the formula: