CS238921B1 - Process for the production of n-alkanone monocarboxylic acids - Google Patents

Abstract

The invention solves a method of producing n-alkane monocarboxylic acids by splitting oxidation of n-alkanones. The procedure is such that n-alkanones with the number of 5 to 11 carbon atoms in the molecule are oxidized with mixing of 50 to 65% by mass. with nitric acid in water at a temperature of 70 to 100 °C and then the n-alkane monocarboxylic acids are isolated by solvent extraction, preferably with diethyl ether. The oxidation can be carried out in the presence of 0.01 to 0.18 wt.%. vanadium oxide. Alkanecarboxylic acids with 5 to 9 carbon atoms can be used for the preparation of ester lubricating oils based on pentaerythritol with alkanecarboxylic acids.

Description

(54) Process for the production of n-alkane monocarboxylic acids

The invention provides a method for producing n-alkanemonocarboxylic acids by the cleavage oxidation of n-alkanones. The procedure is that n-alkanones with 5 to 11 carbon atoms in the molecule are oxidized with stirring with 50 to 65% by weight nitric acid in water at a temperature of 70 to 100 °C and then the n-alkanemonocarboxylic acids are isolated by solvent extraction, preferably diethyl ether. The oxidation can be carried out in the presence of 0.01 to 0.18% by weight vanadium pentoxide.

Alkanecarboxylic acids with 5 to 9 carbon atoms can be used for the preparation of pentaerythritol-based ester lubricating oils with alkanecarboxylic acids.

-238921

I

The invention relates to a method for the production of n-alkane monocarboxylic acids by splitting oxidizing n-alkanones.

There are known procedures for the oxidative conversion of cyclanones by the action of nitric acid to alpha, omega-alkanedicarboxylic acids with the same number of carbon atoms in the chain, but no data have been found on the suitability of the oxidative cleavage of n-alkanones by nitric acid to n-alkane monocarboxylic acids.

Nitric acid used for the oxidative cleavage of C ₄ _^ ₂ olefins ^is used in a wide concentration range, but its optimum range is 50 to 70%. The initiation of the oxidation process is facilitated by the addition of a small amount of alkali metal nitrite.

The molar ratio of nitric acid to ketone is usually 4 to 6:1 in solution. Catalysts are several elements of variable valency, especially V and Cu in solutions of 0.01 to 1%. The initial temperature of the reaction is usually 15 to 100 °C, the final temperature is 50 to 120 °C.

The addition of ketone to nitric acid takes several tens of minutes, the total reaction time is 30 to 300 minutes. The yields of alkane dicarboxylic acid vary in the range of 60 to 70% of theory, nitric acid is reduced in the process to NO and N ₂ O ₄ , which, by reoxidation with oxygen together with water, regenerate nitric acid, but part of it is converted to N ₂ and NjO, no longer capable of such regeneration. Cyclanols can also be oxidatively cleaved in an analogous manner.

The above reaction can be analogously used for the method of producing n-alkanemonocarboxylic acids by the oxidative cleavage of n-alkanones according to the invention, the essence of which is that n-alkanones with 5 to 11 carbon atoms in the molecule are oxidized with stirring with 50 to 65% nitric acid in water at a temperature of 70 to 100 °C and further the alkanecarboxylic acids are isolated by solvent extraction, preferably with diethyl ether.

It is also possible to proceed in such a way that the oxidation is carried out in the presence of 0.01 to 0.18% by weight of vanadium oxide.

Oxidation of n-alkanones with nitric acid is associated with the cleavage of the C-C bond between the carbonyl group in the n-alkanone chain with the adjacent carbon atom, thus leading to the formation of n-alkane monocarboxylic acids. The basic scheme according to which the cleavage of alkanones takes place is as follows:

- ->r ₁ ch ₂ cooh + r ₂ cooh ^R 1 ^CH 2 ^COCH 2 ^R 2'

_- -> _R1COOH + _R2CH2COOH

is a group CHj to and is a group CHj to

The products of subsequent oxidative decomposition to the corresponding lower alkanecarboxylic acids can all be formed from a set of alkanecarboxylic acids. The proportion of reaction on one and the other side of the carbonyl group in the ketone molecule will be determined by the relative strength of the C-H bond on the adjacent carbon: thus methyl-n-alkyl ketones will yield primarily acetic acid from lower carboxylic acids.

The advantage of the method according to the invention is that the expected set of alkanecarboxylic acids is obtained in a high yield, around 90% of theory, while in the case of higher n-alkanones, a predominantly part of the product forms a separate organic phase and only a smaller portion of it is found in the aqueous phase, the essential part of which is diluted nitric acid.

The subject matter of the invention is specified in the examples of embodiments

3892 1

Example 1

A standard apparatus consisting of a heated 250 ml three-necked flask equipped with a KPG stirrer, thermometer, dropping funnel and reflux condenser was used. 0.28 mol of 50 wt. % nitric acid /35.3 g/, heated to 70 °C, and 0.05 g of vanadium pentoxide were charged into the flask.

Then, 0.059 mol (10.0 g) of 4-undecanone was dosed into the flask over 30 minutes and the temperature was maintained at 70°C throughout the reaction, which lasted a total of 300 minutes.

The crude reaction product consisted of two liquid phases; an organic phase (12.42 g), consisting essentially of n-alkanecarboxylic acids C? to Cg, and an aqueous phase, from which, after neutralization with sodium hydroxide, a residue (2.94 g), consisting essentially also of n-alkanecarboxylic acids C2 to Cg, was obtained by three times extraction with the same volume of diethyl ether and its subsequent evaporation; a total of 13.36 g of n-alkanecarboxylic acids ^{C2 to C8} *

The content of individual n-alkanecarboxylic acids in the reaction product from Example 1 (and also other Examples 2 to 8) is given in Table 1.

Example 2

The procedure was as in Example 1 except that the reaction was carried out at 100°C for 60 minutes. The product formed from the organic phase was 9.50 g and that obtained from the aqueous phase was 2.87 g; a total of 12.37 g.

Example3

The procedure was as in Example 1, except that 30.5 58 wt. % nitric acid was added to the flask and the reaction was carried out at 70 °C for 120 minutes. The product formed by the organic phase was 11.20 g and that obtained from the aqueous phase was 1.30 g. Total 12.50 g.

Example 4

The procedure was as in Example 1, except that 27.2 g of 65% by weight nitric acid was added to the flask and the reaction was carried out at 70°C for 120 minutes. The product formed by the organic phase was 11.50 g and that obtained from the aqueous phase was 2.13 g; a total of 13.63 g.

Example 5

The procedure was as in Example 2, except that vanadium oxide was not added to the batch. The product formed from the organic phase was 11.47 g and that obtained from the aqueous phase was 1.23 g; a total of 12.70 g.

Example 6

The procedure was as in Example 2, except that 10.0 g of 2-undecanone was added to the flask (instead of 10.0 g of 4-undecanone). The product formed by the organic phase was 8.94 g and that obtained from the aqueous phase was 2.90 g, a total of 11.84 g.

Example 7

The procedure was as in Example 6, with the difference that 0.335 mol (42.3 g) of 50 wt. % nitric acid, 0.06 g of vanadium pentoxide and further 0.076 mol (10.0 g) of 5-nonanone (instead of 10.0 g of 2-undecanone) were added to the flask.

The product formed from the organic phase was 9.91 g and that obtained from the aqueous phase was 3.76 g; a total of 13.67 g.

Example 8

The procedure was as in Example 6, with the difference that 0.335 mol (70.0 g) of 50% by weight nitric acid, 0.10 g of vanadium pentoxide and further 0.116 mol (10.0 q) of 2-pentanone (instead of 10 g of 2-undecanone) were added to the flask.

The product consisted of a uniform phase, from which, after neutralization with sodium hydroxide, a residue of 15.02 g was obtained by three times extraction with the same volume of diethyl ether and its subsequent evaporation.

Claims (1)

The organic phase product was 9.91 g and obtained from the aqueous phase had 3.76 g, total 13.67 g. Example 8 The procedure was as in Example 6 except that 0.335 mol / 70.0 g was charged into the flask. % 50 wt. nitric acid, 0.10 g vanadium pentoxide and 0.116 radium (10.0 g) 2-pentanone (instead of 10 g 2-undecanone). The product consisted of a uniform phase from which, after being neutralized with sodium hydroxide, a residue of 15.02 g was obtained by extraction three times with an equal volume of diethyl ether and its subsequent evaporation. in phase C2 C3 C4 C5 organ. 0.03 0.87 1.76 0.06 1 aq. 0.13 0.85 1.07 0.09 total 0.16 1.72 2.85 0.15 organ. 0.35 0.99 1.76 0.16 2 W. 0.09 0.99 1.10 0.02 total 0.44 1.98 2.86 0.18 organ. 0.07 0.83 2.02 0.04 3 water. 0.04 0.38 0.44 0.02 total 0.11 1.15 2.46 0.06 organ. 0.05 1.01 2.23 0.66 4 W. 0.05 0.45 0.51 0.03 total 0.10 1.46 2.74 0.69 organ. 0.09 0.85 1.60 0.02 5 W. 0.03 0.32 0.35 0.01 total 0.12 1.17 1.95 0.03 organ. 0.59 0.17 0.14 0.16 6 W. 1.57 0.22 0.21 0.07 total 2.16 0.39 0.35 0.23 organ. 0.70 0.69 3.02 4.10 7 Waters. 0.20 0.33 1.62 1.27 Total 0.90 1.02 4.64 5.37 Organ. - - - - 8 Waters. 1.92 7.48 4.53 - total 1.92 7.48 4.53 - individual n-alkanone monocarboxylic acids C6 / g / C7 C8 C9 C10 total 0.20 2.52 3.08 - - 8.54 0 , 06 0.29 0.43 - - 2.94 0.26 2.81 3.51 - - 11.48 0.46 1, 96 1.89 - - 9.50 0.02 0.28 0.30 - - 2, 80 0.48 2.24 2.19 - - 12.30 0.22 2.37 2.65 - - 8.20 0.01 0.04 0.07 - - 1.00 0.23 2.41 2.72 - - 9.20 0.36 2.89 3.32 - - 10.52 0.06 0.24 0.78 - - 2.12 0.42 3.13 4.10 - - 12.64 0.64 1.88 2.14 - - 7.22 0.01 0.03 0.05 - - 0.80 0.65 1.91 2.19 - - 8.02 0.17 0, 30 0.56 5.12 1.45 8.66 0.06 0.08 0.16 0.16 - 2.53 0.23 0.38 0.72 5.28 1.45 11.19 0.69 - - - - 9,20 - - - - - 3,42 0,69 - - - - 12,62 - - - - - - - 13,93 - - - 13,93 SUBJECT MATERIAL Production method of n-alkan monocarboxylic acids characterized in that n-alkanones having from 5 to 11 carbon atoms in the molecule are oxidized under agitation with dilute acid-binding at a concentration of 50 to 65% by weight. at 70-100 ° C, optionally in the presence of vanadium pentoxide. Severografia, n. P „MOST Price 2.40 Kcs