DE1914688B - Process for the preparation of carboxylic acid nitriles - Google Patents

Description

1 2

It is known. It is particularly advantageous to use sulfamic acid

a mixture of a carboxylic acid or in amounts between about 1 and 2.5 mol and ins-

one of their functional acid derivatives and urinary particular between 1.5 and 2MoI, based on

material heated to a temperature above 25O ⁰ C. 1 equivalent of carboxyl group or carboxyl derivative,

This reaction takes place, as has been found, with 5 and the urea in amounts between about 0.5 and

lower temperature and in a shorter time if 2 moles and in particular between 1 and 1.5 moles

amidosulfonic acid is added to the reaction mixture.

Formula H ₂ N-SO ₃ H) is added. The reaction to the nitrile can be in the presence or

The invention now relates to a method for the absence of an inert solution or diluent

Production of carboxylic acid nitriles can be carried out by heating. So you can

of carboxylic acids or their functional derivatives carboxylic acid, sulfamic acid and urea in

with urea and a condensing agent which is a liquid under the reaction conditions and

is characterized in that the condensate inert, high-boiling organic compound such. B.

Amidosulfonic acid used and that in benzophenone, dissolve or suspend or the

Reaction mixture to a temperature between 180 15 reactants dispensing with an inert one

and 240 ^c C, preferably between 220 and 240 ⁰ C, solvents or diluents melt together

heated. Zen. It is heated until the implementation to

For conversion into the corresponding nitrile nitrile is finished, generally about 30 to 60 minutes, both aliphatic ^ and aromatic, th at a temperature between 180 and 240 ⁰ C and aliphatic-aromatic and heterocyclic carbon 20 preferably between 220 and 240 ^{0 are suitable} C.
acids, e.g. B. Saturated aliphatic monocarboxylic acids After the reaction has ended, the resultant with 2 to 10 carbon atoms, such as acetic acid, pro-nitrile, is separated off in the usual way and the desired pionic acid, butyric acid, hexanecarboxylic acid and octane case are purified. So it can be distilled off from less volatile carboxylic acid, cycloaliphatic carboxylic acids, such as accompanying substances, or with a low-cyclohexane monocarboxylic acid, particularly aromatic-boiling organic solvent, e.g. B. a see, preferably mono- and binuclear mono- and chlorinated aliphatic hydrocarbons, esp-dicarboxylic acids, e.g. B. benzene carboxylic acid, naphthalene special chloroform, trichlorethylene or perchlor-1-carboxylic acid, naphthalene-2-carboxylic acid, diphenyl ethylene, cyclohexane or benzene, and extract an-2-, -3- and -4-carboxylic acid, isophthalic acid, terephthalic acid - then distill. In some cases acid and diphenyl-2,2'-dicarboxylic acid, and heterocyc- 30 the impurities can also be extracted with water,
lische carboxylic acids, e.g. B. monocarboxylic acids hetero- From the Japanese Auslegeschrift 7771/67 is a cyclic 5- or 6-membered rings, which in particular processes for the production of carbonitriles nitrogen, oxygen or sulfur as heteroatoms are known in which one contains alkali or alkaline earth metals, z. B. thiophene-2- and -3-carboxylic acid or salts of carboxylic acids in the presence of phos-nicotinic acid. These acids can contain carbon nitrile chloride and urea or ammonium substituents, e.g. B. halogen, especially salts. This process has several disadvantages of chlorine or bromine, as in chloroacetic acid, 2-chlorine (the starting materials must be reduced to zerpropionic acid and 2-, 3- or 4-fluorine, -chlorine-, -bromine- before mixing; by the Addition of the necessary amount or iodobenzenecarboxylic acid, alkyl groups, as in the phosphonitrile chloride - at least ² I ₉ mol to 1 mol of 2-methylbutyric acid, 2-methyl-3-ethyl-pentanecarboxylic acid salt - creates a considerable amount of acid, 2 -, 3-, or 4-methyl-benzene carboxylic acid, the phosphorus-containing by-products is lost; Methylnaphthalincarbonsäuren, Chinaldincarbonsäu- in some cases the reaction at must energiren very and the 5-methylnicotinic acid, aralkyl radicals such as in see conditions - temperature to 500 ⁰ C - through which 5-benzylnicotiric acid, aryl residues, e.g. phenyl residues, are passed; the reaction initially proceeds violently as in phenylacetic acid, benzthiophene-2-carbon-45, but takes at least about acidic, benzthiophene-3- carboxylic acid or 5-phenyl- 2 hours), which by the process according to the invention thiophcn-2-carboxylic acid, nitro groups, as in 2-, are eliminated, and in a relatively short time and 3- or 4-nitrobenzoic acid, heterocyclic radicals, ins - Easily obtain very pure end products,
particular mononuclear, nitrogen, oxygen or the parts mentioned in the following examples of sulfur as heteroatoms containing 5- or oil-50 mean parts by weight. The temperatures are given in CeI-rige rings, as in the thiophene-2-acetic acid, acyl- sius degrees,
groups, as in the bromobenzophenonecarboxylic acids,

and cyano, mercapto, tert-amino, alkoxy, ^ V Example 1
Ether, ester or organic sulfonyl groups.

Of course, the reaction is only to those 55 128 parts of thiophene-2-carboxylic acid, 194 parts of amido

Carboxylic acids can be used, which are sulfonic acid and 60 parts of urea for 1 hour

temperature are stable, so for example not heated to reflux to 220 to 230 °. Through

Carboxylic acids, which are obtained at the reaction temperature distillation thiophene-2-carboxylic acid nitrile

be decarboxylated. with boiling point 189 °. The yield is 30 ° / _0th

Particularly suitable functional acid derivatives are the 60
ser carboxylic acids are their salts, especially their alkali salts, e.g. B. the sodium and potassium salts, and their example 2
Ammonium salts, their anhydrides, their halides,

z. B. Chlorides, and in the aromatic series, you work as indicated in Example 1, with the

the corresponding trihalomethyl compounds. 65 difference that instead of the 128 parts of thiophene

Examples of functional acid derivatives are ammo-2-carboxylic acid 143 pyridine-3-carboxylic acid

i) ium-2-ch) orbenzoate, acetic anhydride, 4-Mitroben- are obtained, pyridine-3-carboxylic acid nitrile with

zoyl chloride and 4-methylbenzotrichloride. Melting point 49 ° in a yield of _{80 ° / 0.}

3 4

Example 3 ^{extracted by} shaking and filtered. After distilling off

of chloroform, isophthalic acid dinitrile is obtained in

31.4 parts of 2-chloro-benzoic acid, 36 parts of amido-12% yield and with a melting point of 160 ° to 162 °. sulfonic acid and 16.8 parts of urea are mixed together and placed in a vessel with an air cooler 5 B ice ρ ie 1 12
Heated to an internal temperature of 220 to 230 ° for 1 hour.

The 2-chloro-benzene formed is then distilled. If you proceed according to Example 11, with the

zonitrile separated under normal or reduced pressure that the same in place of isophthalic acid

and, if desired, recrystallized from petroleum ether. Amount of terephthalic acid used, one obtains in

The 2-chloro-benzonitrile produced in this way has a 10 ll% yield with terephthalic acid dinitrile

Melting point of 42 °. The yield is 82%, melting point 220 °.

Example 4 Example 13

If you proceed according to Example 3, with the difference, if you proceed according to Example 11, with the sub-

that in place of 31.4 parts of 2-chloro-benzoic acid 15 differed, that in place of 167 parts of isophthalic acid

35.8 parts of 2-chloro-benzoic acid ammonium used, 166 parts of 2-nitro-benzoic acid used, so obtained

are so obtained in 82 ° / _o yield 2-chloro-2-nitro-benzonitrile one in 51 ° / _o yield, having

benzonitrile, melting point 42 °. Melting point 110 °.

Example example 14

If you proceed according to Example 3, with the difference, you replace in Example 13 the 166 parts of 2-nitro

that instead of 31.4 parts of 2-chloro-benzoic acid benzoic acid by the same amount of 3-nitro-benzoe-

35.5 parts of 2-chloro-benzoic acid sodium used, acid, then in 46% yield 3-nitro

2-chloro-benzobenzonitrile is thus obtained in 82% yield.

nitrile, with a melting point of 42 °. 25th . ,

¹ example 15

^For P ' ^{el 6,} if you proceed according to Example 11, with the sub-

If you work according to the instructions in Example 3, it was decided that in place of the 167 parts isophthalic acid

the difference is that instead of 31.4 parts, 200 parts of 2-chloro-5-nitrobenzoic acid are used

2-chloro-benzoic acid, 29.6 parts of 2-chloro-benzoic acid 30 den, is obtained in 66 ° / _o yield 2-chloro-

anhydride is used, the corresponding 5-nitro-benzonitrile is obtained, with a melting point of 104 °.

Nitrile in 82 / _o yield °. The melting point cherishes. .

at 42 °. Example 16

Example 7 If you proceed according to Example 11, with the sub-

35 decided that instead of 167 parts isophthalic acid

If you work according to Example 3, with the lower 157 parts of 3-chloro-benzoic acid is obtained

it was decided that instead of 31.4 parts of 2-chloro-benzoene, 3-chloro-benzonitrile was used in 62% yield

acid 34 parts of naphthalene-1-carboxylic acid used, melting point 39 °.

are obtained in 48% yield naph-. 117

thalin-1-carboxylic acid nitrile, melting point 35 °. 40 B e 1 s ρ 1 e 1 17

. I ₈ If in Example 16 the 157 parts of 3-chloro

Example 8 benzoic acid by the same amount of 4-chloro-benzoe-

If you work according to Example 3, with the difference, acid, you get in 56% yield 4-chloro

that instead of 31.4 parts of 2-chloro-benzoic acid benzonitrile, melting point 93 °.

28 parts of 2-fluorobenzoic acid are used, so 45.

is obtained in 75 ° / _o yield 2-fluoro-benzonitrile Example 18

with a boiling point of 200 °. If you work according to the rules of Example 11,

10 ^m 't the difference that one in place of the 167 parts

^{öebeispiel y} isophthalic acid 200 parts of 2-bromo-benzoic acid

If the procedure of Example 3, with the difference turns 50, is obtained in 86 ^o / _o yield strength ^he 2-bromo-

that instead of 31.4 parts of 2-chloro-benzoic acid benzonitrile, melting point 53 °.
27 parts of phenylacetic acid are used in

48 ° / _o yield phenylacetonitrile, with melting Example 19

point 233 °. If you proceed according to Example 11, with the sub-

B ice ρ ie 1 10 ^{55 scnied> that instead} of the 167 parts of isophthalic acid

250 parts of 2-iodo-benzoic acid are used, this gives

196 parts of benzotrichloride, 194 parts of amidosulfone in 90% yield of 2-iodobenzonitrile, with melt acid and 80 parts of urea are 1 hour below point 54 °.

Heated to reflux to 240 °. After distilling off the bees ρ i e 1 20

The resulting benzonitrile is shaken with 60

a saturated potassium carbonate solution, dries and 46 parts of 2-chloro-benzotrichloride, 36 parts of amido

distilled again. The yield of benzonitrile sulfonic acid and 16.8 parts of urea are

is 51% - the boiling point is 188 °. mixed together and placed in a vessel with an air cooler

ρ. . . ₁₁ 1 hour while stirring at 220 to 240 ° internal temperature

ü e 1 s ρ 1 e 1 11 65 door heated. After cooling, it is mixed with 70 °

167 parts of isophthalic acid, 194 parts of amidosulfone warm water, cooled again, filtered, washed with

acid and 120 parts of urea are 1 hour on an aqueous ammonia solution, dried and distilled

Heated to 240 °. After cooling, it is chlorinated.

2-chloro-benzonitrile is obtained in a yield of 68% with a melting point of 42 °.

Example 21

The procedure of Example 20, with the difference that instead of 46 parts of 2-chloro-benzotrichloride 36 parts of 2-chloro-benzoyl chloride used, 2-chloro-benzonitrile is obtained in a 75% yield, with a melting point of 42 °.

Example 22

If the procedure of Example 20, with the difference that 2-chloro-benzotrichloride 33.4 parts of 4-nitro-benzoic acid used in place of 46 parts, the end product is crystallized from alcohol and is obtained in 72 ° / ₀ sodium Yield of 4-nitro-benzonitrile with a melting point of 147 °.

Example 23

If one proceeds according to Example 20, with the difference that 25 parts of nicotinic acid are used instead of the 46 parts of 2-chloro-benzotrichloride, nicotinic acid nitrile is obtained, which is isolated by extraction with chloroform and distilling off the chloroform. The yield is 68 ° / ₀ , the melting point is 42 °.

Example 24

25.6 parts of cyclohexanecarboxylic acid, 36 parts of sulfamic acid and 16.8 parts of urea are mixed together and heated in a vessel with a reflux condenser to an internal temperature of 220 to 230 ° for 1 hour. After cooling, the residue is extracted several times with warm chloroform. After distilling off of the chloroform, cyclohexanecarboxylic acid nitrile is obtained, which is purified by distillation can be.

The yield is 69 ° / ₀ and the boiling point is 184 °.

Example 25

If in Example 24, 25.6 parts of cyclohexane by 24.5 parts of benzoic acid, is obtained in 75 ⁰ / cent yield benzonitrile, with boiling point 188 °.

Example 26

By proceeding as indicated in Example 24, with the difference that there is used in place of 25.6 parts of cyclohexane, 25 parts of 4-methyl-benzoic acid, one obtains 4-methyl-benzonitrile with a yield of 57 ° / ₀ · Melting point is at 29 °.

Example 27

12.3 parts of 2-chloro-benzoic acid calcium, 12.5 parts of sulfamic acid and 6 parts of urea are mixed with one another mixed and heated in a vessel with an air cooler to an internal temperature of 220 to 230 ° for one hour. The 2-chloro-benzonitrile formed is then distilled off under normal or reduced pressure. The yield is 54% of theory.

Good results are also obtained if the Ca salt is carried out in Example 27 described above equivalent amounts of other alkaline earth metal salts, ζ. B. the Sr or Ba salt replaced.

Claims (3)

Patent claims: 1. Process for the preparation of carboxylic acid nitriles by heating carboxylic acids or their functional derivatives with urea and a condensing agent, characterized in that that amidosulfonic acid is used as the condensing agent and the reaction mixture to a temperature between 180 and 240 ° C, preferably between 220 and 240 ° C, heated. 2. The method according to claim 1, characterized in that that one equivalent of carboxylic acid or carboxylic acid derivative 1 to 2.5 mol, preferably 1.5 to 2 moles, sulfamic acid and 0.5 to 2 moles, preferably 1 to 1.5 moles, of urea are used. 3. The method according to claim 1 and 2, characterized in that the carboxylic acid derivatives the carboxylic acid anhydrides, halides, alkali or ammonium salts or trihalomethyl aromatics used.