JPS6113460B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing 1,5- and 1,8-dinitroanthraquinone. 1,5-dinitroanthraquinone (hereinafter referred to as 1,
5-isomer) is useful as an intermediate for disperse dyes, especially blue disperse dyes belonging to the 1,5-dioxy-4,8-diamino-2-arylanthraquinones, which have high sublimation fastness and brightness. Also,
1,8-dinitroanthraquinone (hereinafter 1,8-
) are disperse dyes, especially monohalogenated dyes.
It is useful as an intermediate for a blue disperse dye which has high definition and is economical, which is mainly composed of 1,8-diamino-4,5-dioxyanthraquinone. Various methods for producing 1,5- and 1,8-isomers are known, but one of them is to dinitrate anthraquinone using a mixed acid consisting of nitric acid and sulfuric acid. 1.
There is a method of separating the 5-isomer cake, then concentrating the separated mother liquor, and crystallizing and separating the 1.8-isomer. Therefore, solid-liquid separation of 1,5- and 1,8-isomers is carried out using a separator such as a centrifuge or a filter press, but the 1,5- and 1,8-isomers obtained by the above method are 1.8-body particles are as small as approximately 20 μm, so they easily cause leakage and clogging.
Conventionally, coarsening of 1.5- and 1.8-body particles has been desired. In view of the above circumstances, the present inventors conducted various studies regarding the coarsening of 1,5- and 1,8-isomer particles. The present invention was completed based on the knowledge that significantly coarsened 1,5- and 1,8-isomers can be obtained if the process is carried out in the presence of the compound. That is, the gist of the present invention is to dinitrate anthraquinone using a mixed acid with a weight ratio of sulfuric acid to nitric acid of 50:50 to 65:35 in an amount such that the molar ratio of nitric acid to anthraquinone is 35 or more, and heat the resulting slurry. After suspension treatment, 1.
Separating the 5-dinitroanthraquinone cake;
Next, the separated mother liquor is concentrated to crystallize and separate 1,8-dinitroanthraquinone, and the mother liquor obtained by crystallizing and separating 1,8-dinitroanthraquinone is reused for the dinitration reaction. - A method for producing 5- and 1,8-dinitroanthraquinone. The present invention will be explained in detail below. In the present invention, anthraquinone is dinitrated by using a mixed acid having a weight ratio of sulfuric acid to nitric acid (hereinafter referred to as mixed acid ratio) of 50:50 to 65:35 in an amount such that the molar ratio of nitric acid to anthraquinone is 35 or more. The upper limit of the molar ratio of nitric acid to anthraquinone is
Although not particularly limited, if the proportion used is too large, the amount of dissolved 1,5-isomer will increase and the recovery rate will decrease, so the dissolution of 1,5-isomer at the mixed acid ratio and the separation temperature described below. Considering the amount, it is best to keep the amount as small as possible to perform a good separation operation of the 1,5-isomer, and usually 150
Selected from a range of about mol or less. It is preferable to use nitric acid and sulfuric acid at as high a concentration as possible, and usually 98% by weight or more nitric acid and 100% by weight sulfuric acid are used. The reaction temperature is generally -20 to 80°C, preferably 10 to 50°C. The reaction mixture obtained in the dinitration reaction is 1.
In addition to the 5- and 1,8-isomers, 2,6-dinitroanthraquinone, 2,7-dinitroanthraquinone, 1,6-dinitroanthraquinone and 1,7
- It is a mixture of various isomers such as dinitroanthraquinone (hereinafter referred to as β-form). The production ratio of these changes slightly depending on the reaction temperature, etc., but 35 to 42% by weight of 1,5-isomer and 1,8-isomer.
The β-isomer accounts for 34-38% by weight, the β-isomer accounts for 19-27% by weight, and the remainder is a by-product that does not have an anthraquinone core. The solubility of each of the above isomers in mixed acid is 1.
The order is 5-form < 1/8-form < β-form, and these solubility ratios vary slightly depending on the mixed acid composition, but
The ratio is approximately 1:4 to 6:20 to 25, and the reaction mixture obtained in the dinitration reaction is a slurry containing most of the produced 1,5-isomer as a solid. The 1,5-isomer solids involve 1,8-isomers, and simply separating them will result in low purity. Therefore, in the present invention, the reaction slurry is heated and suspended, and then the 1,8-isomer is extracted from the slurry. The 5-isomer cake is separated, and the separated mother liquor is then concentrated to distill off nitric acid, which has a large dissolving power, to crystallize and separate the 1.8-isomer. The heating suspension treatment temperature is usually 50 to 90°C, since it is not very effective if it is lower than 50°C, and if it is too high, the product yield will decrease due to side reactions such as nitric acid oxidation.
℃ range, depending on the mixed acid ratio, for example, if the mixed acid ratio is 50:50, it is 75-90℃, if it is 55:45, it is 65-90℃, and if it is 65:35, it is 50-70℃. It is preferable to set it in the range of ℃. The higher the temperature, the shorter the treatment time, for example, 3 to 15 hours at 50℃, 70℃
When the temperature is 1 to 10 hours, the heating time is about 0.5 to 7 hours at 80°C. After the heating suspension treatment, the 1,5-isomer cake is separated from the reaction slurry. Prior to separation, the reaction slurry is heated at 70°C to the extent that the 1,8-isomer does not crystallize.
When cooled to below ℃, preferably 40 to 60℃, 1.
This is preferable because the yield of the 5-body cake is improved and the 1.5-body particles are further coarsened. Separation of 1,5- and 1,8-isomers is carried out using conventionally known separators such as centrifuges and filter presses, and concentration of the mother liquor when crystallizing and separating 1,8-isomers is performed. This is carried out using an evaporator that is used for conventional solvent evaporation. The concentration temperature is usually 40 to 90°C, preferably 40 to 90°C, because if it is too high, impurities will be generated due to side reactions such as nitric acid oxidation, and if it is low, the particle size of the crystallized 1,8-isomer will become small. The temperature is preferably in the range of 40 to 70°C. If the concentration ratio of the separated mother liquor is too high, β-
The amount of crystallized 1,8-isomer increases and the purity of 1,8-isomer decreases.If it is too low, the amount of 1,8-isomer in the mother liquor reused in the dinitration reaction becomes large, resulting in a decrease in the purity of 1,8-isomer. Not only does the purity of the 1.8-isomer decrease, but also the loss of 1,8-isomer increases during the purging of the mother liquor, which will be described later. On the other hand, 1.
When the 8-isomer is used as an intermediate for the above-mentioned blue disperse dye, the contamination of 15% by weight or less of the .beta.-isomer poses no particular problem. Therefore, the separation mother liquor is concentrated so that the β-isomer content in the 1.8-isomer to be crystallized is 15% by weight or less, preferably 10% by weight or less, and the 1.8-isomer to be crystallized is Advantageously, the weight of the anthraquinone is 30 to 45% by weight, based on the anthraquinone starting material. (In this case, the β-isomer content of the 1,8-isomer is usually 5 to 15% by weight.) The present invention is achieved by reusing the mother liquor obtained by separating the 1,8-isomer in the dinitration reaction. , 1・5-
and coarsens 1,8-body particles. This mother liquor consists of a mixed acid containing 1,5-isomer, 1,8-isomer, β-isomer, and by-products, and its composition is different from that of the mixed acid used in the dinitration reaction and other matters when carrying out the present invention. Although it varies depending on various conditions, the mixed acid ratio is usually about 20:80 to 60:40, 1.5-
The content of 1- and 1-8-isomers is about 1 to 12% by weight based on the mixed acid, and the breakdown of these components is about 60% by weight of β-isomer and about 30% by weight of anthraquinone without an anthraquinone nucleus. By-products and about 10% by weight of 1.5-
body and 1.8-body. If the amount of mother liquor used is too small, the sufficient effect will not be obtained, and on the other hand, if it is too large, the impurity β-isomer will accumulate and the purity of 1,5- and 1,8-isomer will decrease. The amount used, expressed on a sulfuric acid basis (weight of sulfuric acid in mother liquor/weight of total sulfuric acid x 100), is usually in the range of 10 to 95% by weight, preferably 30 to 90% by weight, more preferably 50 to 85% by weight. selected and the remainder purged. After the reaction slurry is heated and suspended, the purity of the 1,5-body cake separated from the slurry is:
It is influenced by the amount of mother liquor reused in the dinitration reaction, and when simply increasing the mother liquor reuse rate, the purity is
However, if the nitric acid molar ratio during heating suspension treatment is adjusted according to the amount of mother liquor used, elution and separation of the 1,8-isomer from the 1,5-isomer is efficient. It is possible to obtain even higher purity 1,5-isomers, for example, 90% by weight or more, which is required as an intermediate for blue disperse dyes. The relationship between the mixed acid ratio, the amount of nitric acid and the amount of mother liquor used during heating and suspension is shown in Figures 1 and 2. Figure 1 shows the mixed acid ratio, amount of nitric acid, and amount of mother liquor when using a mother liquor obtained by crystallizing and separating 1,8-isomer with a β-isomer content of 10% by weight according to the conditions of the example described later. It is a graph showing the relationship between and the purity of 1.5-body,
In the figure, the vertical axis shows the amount of nitric acid (molar ratio to the raw material anthraquinone), and the horizontal axis shows the amount of mother liquor used (weight % expressed on the sulfuric acid basis). In the figure, lines 1, 2, and 3 indicate mixed acid ratios of (50:50), (55:45), and (65:
35) and the purity of the 1,5-isomer is 95% by weight, and 1', 2', and 3' are the cases where the purity of the 1,5-isomer is 90% by weight at each of the above mixed acid ratios. shows. Therefore, a 1,5-isomer with a purity of 90 to 95% by weight can be obtained by adopting the conditions surrounded by 1 and 1', 2 and 2', or 3 and 3'. In addition, as mentioned above, the 1-3 and 1'-3' lines are β
The case where the mother liquor separated from the 1,8- body cake with a 1,8- body content is 10% by weight is reused, but when changing the content of the β- body in the 1,8- body, these lines varies somewhat. In other words, if the content of β-isomer increases, the amount of nitric acid decreases, and if the content of β-isomer decreases, the amount of nitric acid increases, but the range of fluctuation is within ±5 weight of the change in the content of β-isomer. %, the amount of nitric acid is about 5 moles. Figure 2 was obtained in the same manner as Figure 1, but the vertical axis shows the amount of nitric acid, and the horizontal axis shows the mixed acid composition (H ₂ SO ₄ /H ₂ SO ₄ +HNO ₃ ×100) in weight%. shows. In the figure, lines A, B, C, and D indicate that the amount of mother liquor used is 30, 50, and 85, respectively.
and 90% by weight, the purity of 1,5-isomer is 95% by weight, and the A', B', C', and D' lines indicate the purity of 1,5-isomer at the above-mentioned amounts of mother liquor used. is 90% by weight. FIG. 2 can also be used in the same way as FIG. 1. Adjustment of the nitric acid molar ratio during the above-mentioned heating suspension treatment can be carried out after the completion of the reaction and before the heating suspension treatment, but considering the amount of nitric acid consumed in the dinitration reaction, It is convenient to adjust in advance. The method of the present invention can be applied to either a batch method or a continuous method, and an example of the process for carrying out the present invention is shown in a block diagram as shown in FIG. 3. As described above, according to the method of the present invention, the particle size of the 1,5-isomer and 1,8-isomer obtained by dinitration of anthraquinone becomes coarse, so that the strain on the filter when separating these is increased. is significantly reduced. In addition, we will greatly reduce the amount of waste sulfuric acid discharged from the manufacturing process, and the amount of 1.
5-bodies and 1.8-bodies can be effectively recovered. Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded. Examples 1 to 13 A steel stirred tank continuous reactor equipped with a continuous feeder for anthraquinone, an external circulation cooler, and a pump for feeding sulfuric acid, nitric acid, and reused mother liquor was charged with HNO ₃ /H ₂ during the reaction. Anthraquinone, nitric acid, sulfuric acid, and reused mother liquor (make-up at the start) are added so that the SO ₄ weight ratio, HNO ₃ /anthraquinone molar ratio, and mother liquor reuse rate expressed on a sulfuric acid basis become the specified values. Temperature 40℃, reaction tank residence time while feeding and withdrawing the reaction mixture.
The dinitration reaction was carried out in 0.6 hours. The extracted reaction mixture was sent to a glass-lined heated suspension tank and treated at a predetermined temperature for about 1 hour, thereby increasing the purity of the 1,5-body cake in the slurry. The slurry extracted from the heated suspension tank is kept at a temperature of approximately 20℃ lower in the suspension tank for a residence time of approximately 3.
The mixture was sent to a crystallization tank, where the partially dissolved 1,5-isomer was crystallized. The slurry extracted from the crystallization tank is passed through a filter equipped with a Teflon cloth, and the mother liquor is thoroughly shaken off. %), the liquid was sent to a 1.8-body crystallization step. On the cake side, in order to prevent purity from decreasing due to adhering mother liquor,
98% nitric acid and ₁₀₀ % _HNO3 : _H2SO4 ratio in the same proportions
The cake was washed by sprinkling 1.5 times the amount of sulfuric acid on the cake, and the cake was washed with water and dried to obtain a 1.5-body cake. For crystallization of 1,8-body, nitric acid in 1,5-body fluid is evaporated using a forced circulation evaporator equipped with an external heater at a temperature of 50 to 60℃ and a residence time of 1 to 1.5 hours. This was done by doing this. The amount of nitric acid evaporated varies somewhat depending on the target cake purity and mother liquor reuse rate, but when the HNO ₃ :H ₂ SO ₄ ratio is 55:45,
_HNO3 /charged anthraquinone=30 to 42 mol/mol, 20 to 30 mol/mol at 65:35, and 50 to 70 mol/mol at 50:50. The slurry extracted from the crystallization tank was filtered, washed with water and dried in the same manner as for the 1,5-body to obtain a 1,8-body cake. The compositions of the 1,5-body cake and 1,8-body cake thus obtained were analyzed using high performance liquid chromatography. The particle size of these cakes was measured by the aeration method. The composition analysis of the mother liquor from which the 1,8-body cake was separated was carried out as follows. First, a sample is taken, water is added to dilute it to an acid concentration of 20% by weight, the precipitated solid substance is filtered, washed and taken out, and this solid substance is analyzed by high performance liquid chromatography to determine the 1,5-isomer, 1・
The amounts of 8-isomer and β-isomer were determined. The solution and washing solution were combined, and the total acid amount was determined by the neutralization method, the sulfuric acid amount was determined by the barium sulfate method, and the amounts of HNO ₃ and H ₂ SO ₄ were calculated. Most of the by-products are nitrobenzoic acid,
Based on the knowledge that these acids are nitrophthalic acids and are sufficiently soluble in a mother liquor with an acid concentration of 20% by weight, the amount of organic matter represented by nitrophthalic acid was approximated from the total carbon analysis value of the acid solution. I asked. The experiments shown in Table 1 were conducted using the above method, and the second
Obtained the results in the table. In both of these experiments, approximately
During 200 hours of continuous operation, there was no substantial change in the yield, composition, particle size, permeability, etc. of each product. Comparative Examples 1-2 Comparative Example 1 is applicable to Examples 1-3, Comparative Example 2 is applicable to Example
Corresponding to cases 12 and 13, these are examples in which the mother liquor is not reused at all. At this time, in order to match the purity of the 1,5-body cake, the HNO ₃ /anthraquinone molar ratio at the time of preparation should be 61.2 mol and 89 mol, respectively. The experimental conditions are shown in Table 1, and the results are shown in Table 2.

【table】

【table】 [Brief explanation of the drawing]

Figures 1 and 2 are graphs showing the relationship between the mixed acid ratio, the amount of nitric acid, the amount of mother liquor used, and the purity of the precipitated 1.5-body cake when the reaction slurry is heated and suspended. , is a block diagram illustrating an example of a process for implementing the present invention.

Claims (1)

[Claims] 1 Dinitration of anthraquinone using a mixed acid with a weight ratio of nitric acid to sulfuric acid of 50:50 to 65:35 in an amount such that the molar ratio of nitric acid to anthraquinone is 35 or more,
After heating and suspending the obtained slurry, a cake of 1,5-dinitroanthraquinone was separated from the slurry, and then the separated mother liquor was concentrated to obtain 1,8
- Production of 1,5- and 1,8-dinitroanthraquinone, characterized by crystallizing and separating dinitroanthraquinone and reusing the mother liquor obtained by separating 1,8-dinitroanthraquinone in the dinitration reaction. Method.