DE1593470C2 - - Google Patents

Description

ammoniaks is inversely proportional to the temperature of the reaction system and the oxidized aldehyde ammonia are removed from the equilibrium system as acid amides, it is preferred to use the whole Keep system at low temperature and continue the introduction of ammonia until the Reaction has ended (until the system is saturated). Another reason the response at lower To carry out temperature is that with an increase in the reaction temperature, the amount of product decreases considerably in amides and increases in nitriles. Aldehyde ammonia can work with others Words are oxidized directly to acid amides at low temperature, while at elevated temperature at the same time undesired dehydration takes place with the formation of imides, the are then oxidized to nitriles.

The yields of products obtained from p-chlorobenzaldehyde at different temperatures, are listed in Table I below.

Table I.

Reaction temperature p-chlorobenzoic acid product (%) p-chlorobenzamide ( ⁰ C) 5.3 p-chlorobenzonitrile recovered
p-chlorobenzyldehyde 92.3 -25 8.6 0 0 89.4 -20 17.4 0 0 72.2 0- 29.0 * 0 0.6 56.6 10 27.9 4.6 3.0 36.5 20th 14.8 13.8 16.0 4.8 35 26.2 34.2 42.0 8.5 78 ^<a> 50.5 10.0

All oxidations were with 0.05Mol aldehyde in 150 ml of ether and 1.3 times the amount of nickel peroxide, based on the theoretical amount (the amount of available oxygen in the oxidizing agent was determined iodometrically), in ether with the exception of (a), where benzene is used as the solvent was carried out for 5 hours.

As is clear from the table above, you can get an excellent yield of acid

NH

R-CH ₂ OH

amides expect only at a reaction temperature below 0 ⁰ C.
The exact nature and the exact mechanism of the described reaction could not yet be fully elucidated, but from the end product, the by-products, the oxidizing agent requirement and the like, one can infer the course of the reaction, as shown in the following equation is.

R-CH = NH - ^> RCM

RCOOH

As can be clearly seen from the above equation, the carboxylic acid can be either from the aldehydes or from the aldehyde ammonia formed in the equilibrium reaction system. However, their formation can be suppressed down to negligibly small values if one keeps the system at a low temperature. Theoretically, a lot of nickel peroxide is needed for the oxidation requires the 1 g-atom of active oxygen per 1 g-molecule Aldehyde can provide, but it is most convenient to use a 1 to 1.5 times or greater amount use (if you use alcohols as starting materials, you need about double the amount of this material), although the use of even higher amounts is not considered harmful.

As a reaction solvent for the invention Process one can use any solvent in which alcohols or aldehydes to a large extent are soluble, and which are difficult to oxidize themselves, e.g. B. ether, benzene, tetrahydrofuran and petroleum hydrocarbons, however, ethers are particularly preferred.

Of the alcohols and aldehydes which are used as starting materials for the process according to the invention NH ₉

R — C — OH

OH

-H ₂ O '

> RCO-NH ₂

Aromatic alcohols or aldehydes are most suitable, as these compounds are used the reaction rates are very fast.

The acid amide yields for various starting compounds are given in Table II below:

Table II

aldehyde

p-chlorobenzaldehyde

o-chlorobenzaldehyde

m-nitrobenzaldehyde

Benzaldehyde

p -cyanobenzaldehyde

p-dimethylaminobenzaldehyde

p-methoxybenzaldehyde

p-methylbenzaldehyde.

Piperonal

Cinnamaldehyde

Furfural

Amide yield

89.4 77.3 88.0 89.2 76.8 57.6 88.3 86.7 85.7 84.7 85.8

5 6

All oxidations were in ether at -20 ⁰ C (84.7 ° / ₀ yield) cinnamamide melting at 149.5 to

accomplished. '150 ⁰ C received.

N-substituted acid amides are in the same way

available if, instead of ammonia, alkyl Example 5
amines used. This implementation always requires a 5 production of furfuramide
longer reaction time, since the oxidation proceeds with a comparatively slow reaction rate. Implementation and work-up using

There were also experiments with cobalt peroxide on furfural (according to the older nomenclature furfural),

Place carried out by nickel peroxide. In terms of in the same way as in the previous one

However, the yields attainable therewith are based on cobalt. Examples were carried out, yielded 4.767 g (85.8 ° / ₀

peroxide inferior to nickel peroxide. Yield) furfuramide with a mp of 141.5 to 143 ° C.

The following examples illustrate the process of

Invention. 'B e i s ρ i e 1 6

. , Manufacture of monomethyl-m-nilrobenzamide
Example 15

Producing benzamide ^{In a Lösun} ° ^»by dissolving 3.023 g

Production of benzamide _{(() Q2 Mq]) rectified} t _{em m} -nitrobenzaldehyde in 150 ml

In a solution that is prepared by dissolving 5.307 g of freshly distilled ether and storing it at -20 ⁰ C

(0.05 mol) of rectified benzaldehyde was kept in 150 ml of ether, dry,

produced under a nitrogen atmosphere and mixed with gaseous monomethylamine.

Cooling with acetone / dry ice kept at -20 ⁰ C leads. Then partially 8.55 g of nickel peroxide were added

became dry Am- containing available active oxygen for about 15 minutes

moniakgas initiated. This solution was then added at 0.026 g-atom, followed by an additional 8 hours

partially mixed with 19.6 g of nickel hydroxide, the monomethylamine introduced at -20 ° C with stirring

Contained 0.065 g-atom of available active oxygen. 25 became. After completion of the reaction, the reaction

After the addition of the nickel peroxide was complete, the mixture was prepared in the same way as before.

Introducing ammonia with stirring at - 20 ⁰ C, whereby 0.867 g (24.1% yield mono-

continued for a period of about 5 hours. methyl-m-nitrobenzamide from m.p. 174 to 175 ° C cr-

After the implementation was over, the were hold,
residue obtained after filtering off thoroughly with 30

washed warm methanol. By evaporation Example 7

of methanol and ether became a dry manufacture of heptamide
Substance obtained after recrystallization

Ethyl acetate 5.405 g (89.2% yield) benzamide from a solution of 5.71 g (0.05 mol) heptaldehyde

F. 130 ⁰ C delivered. · 35 in 150 ml of ether was used for about 5 hours using nickel peroxide as an oxidizing agent

Example 2 Ammonia in the same way as in Example 1

Production of m-nitrobenzamide ^! Γ ^ Α ^ λ ^ ^d fi ^on Seilet, whereby

^& 2.843 g (44.0% yield) heptamide from m.p. 93 to

In a ^{solution kept at -20 0} C from 7.557 g 40 94 ° C were obtained.
(0.05 mol) rectified m-nilrobenzaldehyde in 300 ml

Ether became gaseous for about 15 minutes

Ammonia initiated. Then 18.2 g of nickel were produced from benzamide

peroxide with a content of available acuve (benzalcohol as starting material)
Oxygen of 0.065 g-atom added. Implementation 45

and work-up was carried out in the same manner as in In a mixture obtained by combining 5.409 g

Example 1, whereby 7.307 g (88.0% yield) of m-Ni (0.05 mol) benzyl alcohol and 150 ml of ether and

trobenzamide with a mp of 141 to 142 ° C were obtained. Add 39.27 g of nickel hydroxide at a rate

of available active oxygen of 0.13 g-atom

Example 3 50 (1.1 times the theoretical value, double

Production of p-methoxybenzamide as much as when using aldehyde as the starting material

^ TJ material) was made for about 5 hours

By reacting 6,808 g (0.05 mol) of p-Mcth- ammonia slowly with stirring at ⁰ C --20 single

oxybcnzaldchyd and work-up in practically the headed. The in the same way as in example 1

In the same way as in the example, 6.676 55 were worked up yielded 4.322 g (71.2% yield

(88.3% yield) p-methoxybenzamide from the F. 165 booty) benzamide,
to 167 ° C.

B c i s ρ i c 1 9

Example 4 Production of cinnamic acid amide (from cinnamon alcohol)

Production of cinnamic acid amide °

From 6.71 g (0.05 mol of cinnamon alcohol)

By reacting 6.609 g (0.05 mol) of cinnamon and working up in the same way aklchyd and work-up in the same way as in Example 5.876 g (79.8% yield) of cinnamon 6.231 g of acid amide were obtained from the preceding examples.

Claims (1)

has been described. The expression »Nickel · Claim:,. ..., _Α . ,,. _χ peroxide, as used herein, is used for Process for the preparation of acid amides or designation of the black hydrate higher N-substituted acid amides from the corre- sponding oxides of nickel, which are obtained by reaction between chenden aldehydes or alcohols, thereby 5 a strong oxidizing agent, z. B. Alkali hypo-labeled, that one forms an aromatic halogenite or alkali persulphate, and freshly precipitated tables or «, ^ - unsaturated aldehyde or a nickel hydroxide. corresponding alcohol with ammonia or the preferred in the process according to the invention Alkylamine and nickel peroxide in an amount that is added to the nickel peroxide used by treatment 1 to 1.5 times the theoretically required amount of a nickel salt (e.g. nickel chloride, nickel an active oxygen supplies, in an inert sulfate, nickel carbonate, nickel nitrate) with a strong Solvent at a temperature of -25 to oxidizing agent, e.g. B. Alkali persulfates (e.g.-0? C implements. e.g. sodium persulfate, potassium persulfate) or alkali '___ hypohalites (e.g. sodium hypochlorite, potassium 15 hypochlorite, sodium hypobromite) in an aqueous alkaline medium. Nickel peroxide can The invention relates to a new method for but also by treating oxides of nickel Production of acid amides from the corresponding with an alkali hypohalite in an aqueous Aldehydes or alcohols. · Alkaline medium. That after For the production of acid amides from the nickel peroxide obtained in this way, however, speaking aldehydes or alcohols have usually been less oxidizing,
mainly used the following procedures. One of the preferred ways of manufacturing One consists of at least three stages: Oxidation of highly active nickel peroxide is as follows:
from alcohols or aldehydes to corresponding A solution of 130 g of nickel sulfate hydrate Carboxylic acids (first stage). Conversion of these acids 25 (NiSO ₄ · 6 H ₂ O) in 400 ml of water is added dropwise to their halides, preferably chlorides, esters or with stirring with a solution of 42 g of sodium anhydrides (second stage) and subsequent hand hydroxide in 300 ml 6 ° / ₀ 'according to sodium hypochlorite ment of the derivatives with ammonia (third stage). At staggered. The mixture obtained is stirred for about 30 minutes, the other ammonium salts of carbonic at a temperature between 10 and 25 ° C, acid at high temperature of a heat treatment 30 The black precipitate is filtered off, washed with water to remove active chlorine and it It is generally known that aldehydes are dried with Am- after the cake has been crushed to a powder with monia in solution so-called "aldehyde ammonia" at room temperature. That is nickel peroxide a black fine powder that has a considerable / NH ₂ \ 35 contains amount of water. Based on the results In quantitative analysis, one can use the oxidation R — C — OH means the formula Ni ₂ O ₃ -3 H ₂ O or Ni (OH) ₃ I ascribe, however, its exact structure is not yet available \ HJ known. The nickel peroxide usually contains about . Form 40 0,3 available oxygen to 0.4 · 10 ^-2 g atom per. Many works have been published, grams (by titration of the amount of iodine which is reported by those in which the so-formed aldehyde conversion between nickel peroxide and potassium ammonia is formed by air oxidation with copper complex iodide in acetic acid, with sodium thiocatalyst in ethanol solution or determined by sulfate), of which a considerable part of all-oxidation with lead tetraacetate in aqueous solution 45 is gradually lost when it is heated, but can be oxidized (cf., for example, Rec. trav., remains for a long time if it is at room temperature. 82, p. 757, [1963]; Chem. Ind., P. 988 [1965]). After temperature is stored and protected against atmospheric moisture in this work activity described. However, since the nickel peroxide is in, only nitriles can be obtained. In none of them is a remarkably large ratio to its weight, on the other hand a process is described according to which acid has a surface area, the available oxygen amide can be produced in excellent yield and can be used effectively in the oxidation reaction. Because of this property of the reagent, the Surprisingly, it has now been found that the oxidation according to the invention can advantageously be produced in acid amides in good yield in one step in a short time, usually with almost equivalents. The method according to the invention for 55 quantities of the oxidizing agent to be terminated.
Production of acid amides or N-substituted If you use alcohols as starting materials for the Acid amides from the corresponding aldehydes or processes according to the invention are used, these alcohols are characterized in that an alcohol is immediately oxidized to aldehydes, whereupon the aromatic or α, / J-unsaturated aldehyde or reaction as when using aldehydes as a corresponding alcohol continues with ammonia or 60 starting materials. Since the oxidation of alkylamine and nickel peroxide in an amount that does not provide the alcohols to aldehydes due to the above 1 to 1.5 times the theoretically required amount of publications for the skilled worker in an inert solution explanation, is limited the following agents at a temperature of -25 to 0 ⁰ C reacts. Explanations mainly on the oxidation of processes for the oxidation of alcohols below 65 aldehydes to acid amides. . Use of nickel peroxide as an oxidizing agent, as the so-called »aldehydes are formed already reported (J. O. C; Vol. 27, p. 1597 [1962]) ammoniake "from aldehydes an equilibrium and in the USA. Patents 3,192,258 and reaction, the concentration of the aldehyde