DE1226557B - Process for the production of methyl, ethyl or propyl esters of saturated alpha-alkyl branched fatty acids with at least 4 carbon atoms - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

Number:
File number:
Registration date:
Display day:

C 07c

German class: 12 ο -11

Sch31075IVb / 12o
March 3, 1962
October 13, 1966

The invention relates to a process for the preparation of methyl, ethyl or propyl esters of saturated a-alkyl branched fatty acids with at least 4 carbon atoms from ethylene and / or propylene, carbon oxide and water or methanol 5 under pressure and at a moderately elevated temperature, which is characterized is that the reaction is carried out in the presence of an aqueous solution of hydrofluoric acid (HBF ₄ ) with a content of 84 to 96 percent by weight H ₃ O [BF ₄ ] or a methanolic solution of HBF ₄ with a content of 77 to 100 percent by weight CH ₃ OH ₂ [BF ₄ ].

From the USA.-Patent 2 378 009 it is already known to ethylene with carbon oxide in the presence of BF ₃ · 1.7 H ₂ O and benzoyl peroxide within 10 to 12 hours at 900 to 1100at and 100 to 150 ⁰ C to the ethyl ester of « -Methyl-a-ethylbutyric acid to implement.

In the USA. Patent ^ 2,424,657 a process for the preparation of the ethyl ester of dimethylbutyric acid by reaction of ethylene, propylene and carbon monoxide is described at 900 and 110 ⁰ C in the presence of BF ₃ · 2 H ₂ O.

The disadvantage of this method is that a very high pressure must be applied.

It is also known from German patent specification 942 967 that ethylene and propylene with Convert carbon oxide under pressure to propionic acid or isobutyric acid, whereby one large Excess concentrated sulfuric acid or anhydrous hydrogen fluoride used as a catalyst, but a poor yield is achieved.

CH ₃

+ H © I + CO 3 C ₂ H ₄ -> (C ₂ Hs) ₂ C = CH ₂ > (C ₂ H ₅ ) ₂ C © > (C ₂ H ₅ ) ₂ C ^

Process for the production of methyl, ethyl or propyl esters of saturated <x -alkyl branched compounds
Fatty acids with at least 4 carbon atoms

Applicant:

Schering Aktiengesellschaft,

Berlin 65, Mullerstr. 170-172

Named as inventor:

Dipl.-Chem. Dr. Stephan Pavlenko, Kamen

It has also already been proposed to use aqueous or methanolic solutions of fluoroboric acid for the preparation of fatty acids or their methyl esters from olefins, carbon monoxide and water or methanol. But there it is about the conversion of olefins with 4 or more carbon atoms. Only the process according to the invention permits the use of ethylene and / or propylene for the production of α-alkyl-branched fatty acids catalyzed _{by H 3} O [BF ₄ ] and CH ₃ OH ₂ [BF _4].

If you work with the aqueous HBF ₄ solution according to the invention as a catalyst, 2-ethylbutene-1 is initially formed from ethylene, which easily attaches carbon oxide and water and forms the ethyl ester of a-methyl-a-ethylbutyric acid with another ethylene molecule:

/ CH ₃

+ H ₂ O + C ₂ H ₄

^ COOC ₂ H ₅

With the same catalyst and under the same working conditions, propylene delivers predominantly that Isopropyl ester of isobutyric acid:

C ₃ H ₆

+ Η ©

θ
(CH ₃ ) ₂ - CH

+ CO

(CH ₃ ) ₂ CHCO © H ₂ O + C ₃ H ₆
CO

(CH ₃ ) ₂ CHCOOCH (CH ₃ ) ₂

When a methanolic HBF ₄ solution is used as a catalyst according to the invention, the methanol is not only a solvent but also an esterifying agent at the same time.

In addition, with a suitable choice of reaction conditions, the catalyst concentration and the ratio of carbon oxide to ethylene or propylene possible to conduct the process according to the invention in such a way that fatty acid methyl ester mixtures are used with the desired chain length.

If the process according to the invention is based on ethylene, esters of C ₅ , C ₇ , C _{9 are obtained}

609 «70/422

and ^ fatty acids. If propylene is used as the starting point, then for 2 "hours" spraying takes place at 35 "to"4'5"C 600 g, esters of C ₄ , C ₇ SC ₁₀ and Qg fatty acids are obtained. liquid propylene.

But it is also possible to use an ethylene-propylene 1672 g reaction mixture with 400 g of n-hexane

Use mixture as starting oil. Formed and mixed with 190 g of 65% HBF _4. During the reaction, fatty acid esters with more than 5 carbons separate from two layers. The lower layer consists of lenstoffatomen in the acid radical, then the ester to-1 054 g 79% ig ^he HBF. ₄ The upper organic layer is based on a tertiary acid; the formed is washed neutral with water and fractionated. Fatty acid esters 5 and fewer carbon atoms in the one obtains 392 g of n-hexane, 552 g (4.24 mol) of isobutyric acid residue, such as the methylbutyric acid ester, which is obtained from isopropyl acid ester (b.p. ₆₀ = 120 ° C; VN = 428; n ² S dimerized Ethylene is formed, and the isobutyrate io = 1.3868; df = 0.8505), 85 g (0.95 mol) of isobutyric acid ester, which is formed from propylene, is that of the acid (b.p. ₆₀ = 165.5 ° C ; SZ = 636; n% ° = 1.3920) Ester based on a secondary acid. and 159 g of higher molecular weight esters, predominantly iso-

Although the reaction product contains a proportion of propyl ester of C ₇ fatty acids.

Esters of secondary-C _{4 or.} Contains Cg acids, which - accordingly - 6.1 mol - (- 171 g) CO, -6.1 mol of catalyst are significantly more solid than esters of tertiary fat - 15 (110 g) H ₂ O and 12.15 mol (515 g) bind propylene for the acids. And only consumed outside the pressure reactor formation of the reaction products, whereby this can be separated from the catalyst, the consumed propylene allows the individual present state of the process technology to distribute a bond as follows :. For the. Isopxopylestef continuous execution of the isobutyric acid ^{according to the invention r} 8.4SMoI = 69.7%, for the Iso process. 20 butyric acid 0.95MoI = 7.8% and for the isopropyl

The continuous embodiment of the inventor. C ₇ fatty acids 2.72 moles = 22.5%. The process according to the invention is characterized in that it contains products of synthesis with respect to the fact that ethylene and / or propylene are used and that propylene (600 g) is 85.7%. . : ·. : HBF ₄ solution in a continuously running. ·:;:., -. :. \

Cycle process continuously introduces into the pressure reactor, 25 ■::. . . -,: ..

an aliquot of the reaction mixture from the. Example3

Reactor discharges continuously and the catalyst through; . . - -. . . :. .:

Countercurrent washing with water or methanol except SOQ.g

half of the reactor separates the catalyst from the reaction mixture. of composition 72.45 weight and returned to the reactor again. '' 30 percent HBF ₄ , 0.65 percent by weight HF and 26.9 Ge?

A particularly advantageous embodiment of the weight percent anhydrous methanol presented, then The method according to the invention is characterized by carbon oxide at 40 ° C. up to a partial pressure of draws that the reaction at 50 to 150 at, 100 at and ethylene up to a partial pressure rvon preferably at 100 to 150 at, total pressure and at 40 at. While maintaining a response Performs 20 to 50 ° C: 35 temperature of about 40 to 45 ° C and a total

• ·· - * pressure of 140 at is pressed in the course, from 3 sttin-

Example of about 3901 (about 490g) ethylene. -.

From the 1625 g of reaction mixture obtained,

In a 5 l V4A magnetic stirrer autoclave, 900 g of the 846 g of a catalyst having a composition of 78.6% by weight per fatty acid ester mixture are obtained after the catalyst has been separated off. Like in. Example 1 cent HBF ₄ , 0.85 percent by weight HF and 20.55 percent by weight are also obtained here, after separation by distillation, overweight percent H ₂ O, then weighed at 40 ° C carbon. Esters of ^ -fatty acids, namely 469 g of oxide up to a partial pressure of 100 at and ethylene = 55.5% of the total amount: _{b.p. 2o} = 50 to 52%; pressed up to a partial pressure of 50 at ^ where VZ = 386 (calculated 390); nl ° == 1.4092; d% = 0.8789; the total pressure due to constant addition of ethylene 45 molar weight = 143 (calculated 144) ... - ■ .. ■ .-, ... "and carbon monoxide in a ratio of 4: 1 to 150 at and the other synthesis products are methyl esters of others

■ Reaction temperature through gentle heat supply, fatty acids with an uneven carbon number, namely: is kept at 40 to 45 ° C. In the course of 4 hours - C ₅ = 80 g (9.4%), C ₉ to C ₁₃ = 245 g (28 ^ 9%), higher than the absorption of about 25 moles of ethylene than C ₁₃ = 52 g ( 6.2%)
and about 6.5 moles of carbon oxide instead. 50

The distillation of the organic layer of Reak-Example 4

tion mixture provides 857 g (5.35MoI) of a-methyl

Ethyl α-ethylbutyric acid, _{boiling point 20} ° -63 ° C .; VZ = 350 900 g

(calculated 353); Molecular weight '== 159 (calculated 158); Catalyst of the composition 59.4 Gewichtspro- nl ° = 1.4107, df = 0.8737. 55 percent HBF ₄ , 1.1 percent by weight HF and 39.5 percent

In addition, 24 g (0.19 mol) «-Methylbutter- weight percent anhydrous methanol are presented, then acid ethyl ester (bp. ₂₀ = 42 ° C; VZ = 429, nf carbon oxide up to a pressure of 140 at- = 1.3988) ; 68 g (0.59 mol) of a-methyl-a-ethylbutter presses. In the course of 2 hours, then is injected with acid a (Kp _2o = 113 ° C; n = 1.4239% °; 430 = SZ.) And 35 to 45 ^P C of liquid propylene.
22 g of distillation residues obtained. 60 From the 1756 g of reaction mixture obtained

after adding 800 g of n-hexane and 210 g of methane

Example 2 ⁿ ° l 850 g of the re-usable catalyst

(59.1 percent by weight. HBF ₄ ) as the lower heavy phase

900 g are separated off in a 5 l V4Ai magnetic stirrer autoclave. '. . . :

Catalyst with a composition of 79.3 percent by weight. The organic cent HBF ₄ , 1.0 percent by weight HF and 19.7 Ge layer, washed _{neutral with water, is submitted to careful fractionation with a weight percentage of H 2} O - and then CO is thrown up. This gives 992 g of a fatty acid pressed under a pressure of 140 atm. Within mix, consisting of:. .: · Τ. :.

ίο

1. 12.2% (121g, 1.19MoI) methyl isobutyrate; Κρ. _7β0 = 92 ° C; Molecular weight = 102 (calculated 102); nf = 1.3821; d? = 0.8824 ;;

2. 33.8 7o (336 g, 2.59 moles) methyl esters of C ₇ fatty acids; Kp _2o = 48 to 50 ⁰ C. Molecular weight = 146 (calculated 144); nf = 1.4089; d * $ = 0.8788;

3. 30.0 ° / ₀ (297 g, 1.60 mol) Methylester of C ₁₀ fatty acids; B.p. ₂₀ = 90 to 94 ^° C; Molecular weight = 185.5 (calculated 186); rig = 1.4277; d? = 0.8766;

4. 21.3 7o (215 g, 0.95 mol) methyl esters of C ₁₃ FeW acids; Bp ₆ = 85 to 105 ^° C; n% ° = 1.482; rff = 0.8762.

The distillation residue consists of 2.3 7 "(23 g) higher molecular weight esters.

The yield of synthesis products, based on the propylene used, is thus 725 g (917o)

Claims (3)

Patent claims: 1. A process for the preparation of methyl, ethyl or propyl esters of saturated a-alkyl branched fatty acids with at least 4 carbon atoms from ethylene and / or propylene, carbon oxide and water or methanol under pressure and at moderately elevated temperature, characterized in that the reaction is carried out in the presence an aqueous solution of hydrofluoric acid (HBF ₄ ) with a content of 84 to 96 percent by weight H ₃ O [BF ₄ ] or a methanolic solution of HBF ₄ with a content of 77 to 100 percent by weight CH ₃ OH ₂ [BF ₄ ]. 2. The method according to claim 1, characterized in that the reaction at 50 to 150 at, preferably at 100 to 150 at, total pressure and at 20 to 50 ⁰ C is carried out. 3. The method according to claim 1 and 2, characterized in that ethylene and / or propylene and the HBF ₄ solution is continuously introduced into the pressure reactor in a continuous cycle, an aliquot of the reaction mixture is continuously discharged from the reactor and the catalyst separated from the reaction mixture by countercurrent washing with water or methanol outside the reactor and returned to the reactor again. 609 670/422 10.66 © Bundesdruckerei Berlin