DE2103360C - - Google Patents

Description

I.s is known to produce 1-nitroanthraquinone by nitration before making anthraquinone with nitric acid. Larger ones are formed in the presence of sulfuric acid Amounts of by-products, mainly dinitroanthraquinone in addition to 2-nitroanthraquinone. In addition, remains one·; certain amount of anthraquinone not converted back. The purification of the 1-nitroantirachinone thus obtained is cumbersome and makes the process more expensive.

It has now been found that 1-nitroanthrachhor: in particular purity and in a particularly economical manner by nitrating anthrachiion can produce with nitric acid if you nitrate in the presence of phosphoric acid and the Water content of the reaction mixture at the start of the reaction does not exceed 16%.

The phosphoric acid is particularly expediently used in amounts of at least 1 mol and preferably of IC Dis 40 mol, based on 1 mol of the anthraquinone to be nitrated. It preferably contains more than 61% PjO ₅ (the acid content of phosphoric acid _{being calculated as the P a} O _t content), in particular more than 70% P ₂ O ₅ . (Percent is understood here and in the following to mean percent by weight.) It is also possible to use polyphosphoric acids and phosphorus pentoxide.

The nitrating agent used is preferably nitric acid in amounts of at least L mol, particularly advantageously from 3 to 13 mol and in particular from 4 to 8 mol, based on 1 mol of anhraquinone. It is particularly useful to use 90 to 100 percent, especially 95 to 98 percent, nitric acid. 40 to 90 percent nitric acid can also be used, do: h in this case, highly concentrated phosphoric acid or P, O _{ ,. Instead of nitric acid, water-soluble nitrates, e.g. B. ammonium nitrate, can be used as a nitrating agent.

The reaction mixture can also contain sulfuric acid. This can as such or in the form of SO ι or Alkalinwtallsulfaten, for example Na ₁ SO ₄ , in amounts of about 0.01 to 0.1 mol and in particular from 0.03 to 0.05 mol, based on 1 mol of anthraquinone , be admitted. SO ₃ can also be added as a dimethylformamide-SO ₃ complex.

The reaction mixture preferably contains not more than 5 % water if the reaction mixture is used.

The reaction temperature can be chosen within a wide range. So between about 0 ⁰ C and the boiling point of the reaction mixture under normal pressure and at higher Tempe-

Temperatures, for example up to 125 ⁰ C, are nitrided under increased pressure. Preferably anthraquinone is converted at 30 to 90 ⁰ C and in particular at 40 to 7O ⁰ C in 1-nitroanthraquinone. Since water is formed in the course of the reaction, the reaction can

ίο by adding more nitric acid, phosphoric acid, Polyphosphoric acids and / or phosphorus pentoxide are accelerated.

The reaction mixture can be heated until a complete or almost complete conversion

The anthraquinone has settled. However, in some cases it is also advantageous to interrupt the reaction, z. B. when 50 to 90% of the anthraquinone used have reacted. In the latter If the l-nitroanthraquinone obtained is separated

so off and use the filtrate for a new approach, optionally after restoring the original concentration of nitric acid and phosphoric acid made.

The reaction product can be iso-

s5 be lated, e.g. B. by filtering off after cooling of the reaction mixture: .. If desired, it can be washed with water and dried. It consists mainly of 1-nitroanthraquinone and contains no more than small amounts of the starting product and by-products.

It was not expected that the addition of phosphoric acid would lead to useful results in the nitration of anthraquinone, since in K i r k-Othmcr. Encyclopedia of Chemical Technology 9,

P. 317, the addition of phosphoric acid is generally not recommended.

The results obtained in U.S. Patent 2,874,168 could not be confirmed by the inventor will. This is in line with H ο übe n-We y 1, "Methods of Organic Chemistry", Vol. X / l (1971), p. 614.

The parts mentioned in the examples are parts by weight and the percentages are percentages by weight. The temperatures are given in degrees Celsius.

example 1

13 parts of anthraquinone and 100 parts of crystallized, 98% strength phosphoric acid are heated together to 45 °. At this temperature, 20 parts of PS% nitric acid and 0.5 part of sulfur trioxide are added over the course of 30 minutes. After stirring for 24 hours at 40 ° to 45 °, thin-layer chromatography shows that about 50% of the conversion to 1-nitroanthraquinone has taken place. The reaction mixture is allowed to cool to 25 °, the product which has separated out is filtered off with suction and washed with water until the filtrate is neutral is, and dries it. It contains 96% 1-nitroanthraquinone and 4% anthraquinone. The yield is 7 parts. The filtrate contains anthraquinone in addition to a little 1-nitroanthraquinone. It can be used again after the water content has been brought to the original value by adding polyphosphoric acid with a P ₁ O _{6 content of 83 to 84%.}

Example 2

In a mixture of 100 parts of 98% igar phosphoric acid and 30 parts of 98% nitric acid are used

at 20 to 25 ° 13 parts of anthraquinone heats the Mixture to 45 ° and stir it for 6 hours. The conversion is? .5%. The 1-nitroanthraquinone obtained contains only traces of dinitroanthraquinones.

Details in Example 4. The product obtained (17.2 parts) consists of 90% 1-nitroanthraquinone, 2% 2-nitroanthraquinone, 5% dinitroanthraquinones

and 3% anthraquinone

Example 6
The procedure is as indicated in Example 4

where ^ ^^^^^

and 50 parts of 84% phosphoric acid was added heated 45 ° Man ¹⁰ J 'J ^ ⁵ "StSnauf. The yield is heated: slowly to 70 ° and stirred for 13 hours at this i. pe ersauf IfIS ttmdenau ^ _drying

Temperature. The anthraquinone dissolves completely in the reaction mixture during the amount of 22, o leiie ^einc: > ^ri _u .__ J _<OI Ref.klion, while the 1-nitroanthraquinone with a little diritoanthraquinones crystallizes out, 2-nitroanthraquinone leads with it a large proportion of dinitroanthraquinone 15 / µs is always dissolved. The conversion is 50%. The iso-

Example 3

1Λ parts of anthraquinone are at room temperature entered into a mixture of 50 parts of 98% strength nitric acid and 50 parts of 84% strength phosphoric acid. Man

, 0 lights "

from 87% 1-nitroanthraquinone, 2.5% 2-nitrcanthraquinone, 8% üinitroanthraquinones, 2% anthraquinone and 0.5% other by-products.

üer.e 1-nitroanthraquinone contains 3 ^ / ₀ anthraquinone (• nc ·, only traces of dinitroanthraquinones.

Example 4

In a mixture of 22.4 parts of anthraquinone and parts of 100% phosphoric acid are in the course of 30 minutes 4; Parts of 98% nitric acid added. The mixture is warmed to 45 ° for 16 hours. After filtering through a GS glass suction filter, Washing with water and drying gives 20.5 parts of a product which is 90% 1-nitroanthraquinone (70% of theory), 1% 2-nitroanthraquinone, 8% dinitroanthraquinone and 1% anthraquinone

contains. _n . . . ,

Example 5

22.4 parts of anthraquinone, 180 parts of 99.5% phosphoric acid and 36 parts of 98% nitric acid are used and heated to 45 ° after 22 hours

Example 7

The procedure is as indicated in Example 4, but 22.4 parts of anthraquinone, 1 & 0 parts of 99% phosphoric acid and 27 parts of 98 ° / _? iger salt ao pitric acid 16 hours at 45 °. After filtering and drying, the yield is 18 parts of a product which contains 90% 1-nitroanthraquinone, 8% dinitroanthraquinones and small amounts of 2-nitroanthraquinone and anthraquinone.
The following table gives further examples of reaction conditions for the preparation of 1-nitroanthraquinone according to the invention.

The yield given under (a) refers to that in a conventional manner by pouring Product obtained on ice, the menr of / I-nitro- and dinitroanthraquinones is contaminated; the yield given under (b) relates to the significant purer product obtained by filtering the reacted mixture.

example

Teüe
Anthraquinone

phosphoric acid

Dear

concentration

'L

nitric acid

Parts

Concentration

temperature

8th
9
10
11th
12th
13th
14th
15th
16
17th
18th
19th
20th
21
22nd
23
24
25th

20.8
20.8
20.8
20.8
20.8
20.8
20.8
20.8
104
104
104
104
104
104
104
104
13th
52

167
167
167
167
167
167
167
154
836
668
752
836
836
836
836
836
50
418

98
100
101.5
99.5
99.5
100
100
100
101.5
100
100
100
100
101.5
103.5
101.5
85
101.5

25th
25th
33.4
20.8
46
41.8
41.8 43.3 210
149
167
186
186
210
210
210
75
74

98

98

98

98

98

98

98

98

98

98

98

98

98

98

98

98

98

98

45

45

45

45

45

45

45

45

45

45

45

45

50

43

45

45

73

60 time

hours

Mo'i ratio
Anthraquinone /
ENT,

Salts

(Parts)

(a)

Yield:
° / o the
theory
1-nitroanthra
chinone

sales volume

Yield: · /. the theory 1-nitroanthra quinone

16 . 3.9 16 : 3.9 18th : 5.3 18th : 3.3 18th .: 7.8 20th .: 6.6 16 [: 6.6 20th 1 · 6.9 < 15th 1 6.6 < 16 1: 4.72 16 1 : 5.3 16 1 ; 5.9 16 1 : 5.9 16 1 : 6.6 1 : 6.6 11th 1 : 6.6 32 1 : 6.6 20th 1 : 6.6 I.

(Q ₁ ) Na ₂ SO ₄
(9) NH ₄ NQ

(40)
NH ₄ NO ₃

46
60
74
46
67
70
76

75
56
68
69
75
75
73
73

69

99

50

100

80

65

40
95

40 50 71 36 58 62 65

Claims (4)

Patent claims: 1. Process for the preparation of 1-nitroanthraquinone by nitriding! of anthraquinone with nitric acid, characterized by that nitration is carried out in the presence of phosphoric acid and the water content of the reaction mixture at the start of the reaction is not more than 16% amounts to. 2. The method according to claim 1, characterized in that the reaction mixture is no longer contains more than 5 percent by weight of water. 3. The method according to claim 1, characterized in that nitriding at temperatures between 30 and 9O ⁰ C. 4. The method according to claim 1, characterized in that per mole of anthraquinone at least 1 mol and preferably 10 to 40 mol of phosphoric acid and at least 1 mol and preferably 3 to 13 mol of nitric acid are used.