DE1119840B - Process for the production of ª-diketones - Google Patents

Description

The invention relates to processes for the preparation of / 9-diketones of the general formula

R • CH ₂ • CO • CHR ₁ • CO • CH ₂ • R ₂

in which R, R ₁ and R _{2 represent} saturated or unsaturated, branched or unbranched acyclic hydrocarbon radicals having 1 to 21 carbon atoms, R, R ₁ and R ₂ are preferably the same, but they can also be different.

According to the invention, β-diketones become the above Formula prepared by adding acids of the general formula

R-CH ₂ -COOH

in which R has the meaning given above, and / or anhydrides of these acids are ^{condensed at temperatures between 150 and 220 0} C in the presence of oxygen-containing boron compounds with elimination of carbon dioxide, the water released during the reaction being removed immediately after its formation, and the water obtained Hydrolyzed reaction mixture.

When diketones are formed from carboxylic acids, 3 molecules of carboxylic acid become 1 molecule Carbonic acid and 2 molecules of water are split off.

Some of the acid and / or the anhydride used as starting material can be replaced by a monoketone of the formula RCH ₂ · CO · CH ₂ R ₁ .

The catalysts used are oxygen-containing boron compounds, which are acidic in nature have or are capable of forming compounds of an acidic nature, d. H. by reaction with OH or COOH groups can form esters or anhydrides during the reaction. There are inorganic ones Boron compounds such as boric oxide, boric acid and salts of boric acid with weak or volatile bases, such as Zinc borate and ammonium pentaborate, organic boron compounds such as esters of boric acid and mixed anhydrides boric acid and organic acids, e.g. B. the trimethyl ester, triethyl ester or mannitol ester Boric acid, the mixed anhydride of boric acid and acetic acid and the mixed anhydrides of boric acid and higher fatty acids into consideration. Borax and oxidizing boron compounds such as perborates are less common suitable.

The procedure can be carried out under normal or reduced pressure. The reaction mixture can be kept at the boiling point of the mixture, and the carboxylic acid which is distilled off can be condensed and, after removal of water, added to the reaction mixture again. Man method of manufacture
of ß-diketones

Applicant:
Unilever NV, Rotterdam (Netherlands)

Representative: Dr. E. Wiegand, Munich 15,

and Dipl.-Ing. W. Niemann,
Hamburg 1, Ballindamm 26, patent attorneys

Claimed priority:
Great Britain of August 30, 1957 (No. 27 444/57)

Dr. Johannes Donats von Mikusch-Buchberg,

Hamburg-Harburg,
has been named as the inventor

can also use a solvent with a suitable boiling point. The solvent is then partially distilled off together with any water formed, condensed and separated from the water, whereupon all or part of it can be added back to the reaction mixture. After the condensation has ended, the reaction mixture is treated with a hydrolyzing agent, preferably hot water, and the residue, e.g. B. by decanting and distilling, purified.
In the preparation of the products according to the invention, acid anhydrides or a mixture of monoketones and acid anhydrides can be used as the starting material and boric oxide or boric acid as the catalyst. Acids can also be used as the starting material, but the reaction then proceeds more slowly than when starting from acid anhydrides or a mixture of monoketones and acid anhydrides. In many cases, however, the use of acids is technically more expedient.
Acids that can be used as such or in the form of their anhydrides in the condensation are, for. B. unbranched saturated monocarboxylic acids such as propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, palmitic acid and stearic acid, branched saturated monocarboxylic acids such as isocaproic acid, and. unsaturated monocarboxylic acids such as 4-hexenoic acid, oleic acid, linoleic

109 750/554

3 4

acid and erucic acid. Terminally unsaturated acids,. Example 2
like vinyl acetic acid, have a tendency to polymerize unless special precautions are taken to counteract a mixture of 195 g of propionic anhydride. (1.5 moles) and 129 g of diethyl ketone (1.5 moles) at 34.8 g

If the hydrocarbon radicals are unsaturated, 5 boric anhydride has been left in a flask provided with a reflux column for 11 hours care must be taken to avoid polymerization as much as possible. A polymerization boils, with the internal temperature from 120 to 156.5 ° C mostly occurring when the degree of unsaturation increased. After removing the reflux column left is high. So fatty acids like linolenic acid and 132.6 g of propionic acid are distilled off. The reverse fatty acids that were formed conjugated double bonds were extracted several times with hot water, such as wood oil fatty acids (tung oil fatty acids) or the remaining 79.5 g of boron-free product octadeca-9, ll-dienoic acid, are less suitable. Mixtures were distilled at a pressure of 12.5 mm mercury of fatty acids, which did not have a too high content of column. At 78 to 85 ° C, 50 g of such acids were included, z. (3,5) on which at erFettsäuren of fish oils, however, can be successfully neuter distillation at 15 for the most part at 78 ⁰ C apply as linseed oil fatty acids, or of the crude 4-Methylheptadion-. Fatty acids with one double bond, such as boiled at a pressure of 12 mm of mercury and oleic acid, or with two non-conjugated double bonds, had a refractive index of nff = 1.4431. When bindings, such as linoleic acid, are very suitable. Before shaking with aqueous copper acetate solution, mixtures are preferably used which contain an er / S-diketone, a characteristic copper enolate with a considerable amount of these fatty acids, e.g. B. the 20 has a melting point of 181 ° C.
Fatty acids from soybean oil, cottonseed oil, peanut oil,. . ₁
Rapeseed oil or tall oil or the corresponding anhydrides. Example Ä

The diketones can be used as intermediates in a mixture of 200 g of caprylic anhydride and

organic syntheses and in the preparation of 13 g of boric oxide was carried out under nitrogen sparging

Plasticizers or drilling oils are applied 25 to 10 for 8 hours at atmospheric pressure

especially if it ^{heated saturated hydrocarbon 21O 0} C, whereby 6.8 g of carbonic acid were released,

chains included. They are also valuable as drying The reaction vessel was then evacuated,

Components in paints, varnishes, linoleum whereupon 74.3 g of caprylic acid at a pressure of

and similar products, if they distilled off several times less than 20 mm of mercury,

Contain saturated hydrocarbon chains. 30 The residue obtained (131.5 g) was hydrolyzed

The products obtainable according to the invention and by boiling seven times with water from

stand from colorless crystals or from liquids, boric acid exempt. The dried residue that

which, depending on its molecular weight, weighed 114.4 g more or less viscous, was fractionated in vacuo, with

are, and have a color that is between light yellow and 51.5 g of caprylic acid and 41.3 g of essentially one

can lie brown. 35 fractions consisting of 9-hexyl-heptadecadione- (8,10)

The invention is obtained in more detail by means of examples; the faction went to one

explained. Pressure of 1 mm of mercury at 173 to 180 ^° C

Example 1 Waer. ^ ^{S ze} ISTE is that it has an acid number of 1.7 and

a molecular weight of 350 (calculated value 352)

1 mole of caproic anhydride (214.3 g) was had at 40%. The diketone gave a strong one with ferric chloride

5% boron oxide (10.7 g) in a nitrogen stream for 9 hours red color,

the at atmospheric pressure with gentle stirring on ice cream 4

200 ⁰ C heated. In this case, 7.5 g of carbon dioxide were corresponds ^P

wraps. A mixture of 150 g of oleic acid and 4.6 g of boric acid under reduced pressure, 52 g of caproic acid ab- 45 anhydride was then distilled from this reaction mixture at a pressure of less than 1 mm. The residue was purified by six times heated from boron oxide and mercury for 20 hours at 200 to 21O ⁰ C other boron compounds formed during the heating in a vessel equipped with a fractionating column Reakbefreit it with hot water gewä- tion vessel. The column was heated so that it was seen and then fractionally distilled. Liberated water and carbon dioxide (in total in addition to some caproic acid, 44 g of a main 50 13.4 g) were able to distill off, while the higher fraction was obtained, the parts boiling at a pressure of 10.5 mm flowing back into the reaction mixture. Mercury column distilled at 175 to 178 ° C. This crude product had an acid number of 30 and one fraction consisted of over 90% of the organic boron boiling 7-butyltridecadione (6th) formed during the reaction to hydrolyze all of the organic boron boiling points 7-butyltridecadione (6th , 8) with the following 55 compounds was boiled with water, and it was washed until all boric acid formed in this way was

Acid number 0 was ^removed -

, ..., "' \ ' ₀ - _c To remove the ones present in the product

verseiiungszam in _frden, 5 _{fatty acids} ^ _{Γ (1ε d} i _eses it in a distillation process

Carbonyl number 210.5 _6o lier flask heated to 220 ° C and at a pressure of

Molecular weight 268 0.5 mm mercury column for 20 minutes at this temperature

Density held at 25 ⁰ C 0.8825 temperature, with about 12 percent by weight decreasing

Refractive index 1.4480 distilled ...

, .. ,,. ,. _o , ,, The residue (94 g) consisted essentially of

Molecular refraction 81.43 ^ _{the diketone} i ^ hexadecen-tp-ylheptatriacontadiene-

When treated with ferric chloride, the pro- (9.28) -dione- (18.20) and had an acid number of 5, one duct has a dark red saponification number of 76, which is characteristic of jS-diketones, and a molecular weight of Colour. 789 (calculated molecular weight = 767.4).

Example 5

The process according to Example 4 was carried out, except that oleic acid was replaced by linoleic anhydride and the mixture was heated ^{to 210 ° C. for 6 hours.}

In this way, 97 g of an oily residue were obtained, which essentially consists of the diketone 19-hexadecadiene- ^ lOO-ylheptatriaconta-tetraene - ^^ S ^ l) -dione- (18.20) duration.

Example 6

A mixture of 17 g Capronon (Vi ₀ mol) and 21.4 g caproic anhydride (Vi ₀ mol) was treated with 1.92 g of B ₂ O ₃ (5%) in a round bottom flask for 2 hours at ordinary pressure in an oil bath of 190 ° C and two more hours in an oil bath heated to 210 ⁰ C was heated with mechanical stirring in a nitrogen atmosphere. To remove the boric acid, the product was boiled several times with water, some of the free caproic acid formed also going into solution. The remaining 24.8 g of boric acid-free substance were fractionated at a pressure of 1 mm of mercury. After a forerun consisting essentially of caproic acid of 9.8 g and an intermediate fraction of 1.1 g, 11 g of the crude /? - diketone passed over at 150 to 154 ° C. This product showed a strongly positive iron (III) chloride reaction and, on renewed fractionation at a pressure of 1 mm of mercury, gave 9.23 g of the 7-butyltridecadione (6.8) described in Example 1.

Claims (6)

PATENT CLAIMS: 1. Process for the preparation of / 3-diketones the general formula RCH ₂ • CO • CHR ₁ • CO • CH ₂ R ₂
in which R, R ₁ and R ₂ denote acyclic hydrocarbon radicals having 1 to 21 carbon atoms, characterized in that acids of the general formula R-CH ₂ -CO-OH is in which R has the abovementioned meaning, and or or anhydrides of these acids at temperatures of 150-220 ⁰ C in the presence of oxygen-containing boron compounds preferably under reflux under carbon dioxide elimination condensed to give the liberated during the reaction, water immediately after its formation removed, and the reaction mixture obtained is hydrolyzed. 2. Modification of the method according to claim 1, characterized in that part of the acid and / or the anhydride in the reaction mixture by a monoketone of the formula RCH ₂ • CO • CH ₂ • R ₁ in which R and R _{1 have} the meaning given above, is replaced. 3. The method according to claim 1 and 2, characterized in that the condensation in one Stream of an inert gas is carried out. 4. The method according to claim 1 to 3, characterized in that the condensation under reduced Printing is carried out. 5. The method according to claim 1 to 4, characterized in that the condensation in the presence carried out by boron oxide. 6. The method according to any one of claims 1 to 5, characterized in that one unsaturated Carboxylic acids or their anhydrides or unsaturated ketones are used as starting compounds. © 109 750/554 12.61