DE1668484C3 - Process for the production of butyraldehydes - Google Patents

Description

Various processes are known which enable CU aldehydes to be obtained by hydroformylation allow propene with CO and H2 in the presence of simple or modified cobalt carbonyls. Under these conditions, isobutyraldehyde (normal: branched im Ratio 3-4: 1). So far, no processes have become known that the synthesis of aldehydes where the ratio of normal to branched isomers is above 5: 1

Oxo products with high ratios of linear to branched-chain isomers can, according to FR-PS 13 45 933 are obtained by hydroformylation of propene; in the products obtained it is However, they are mixtures of CvAWehydes and alcohols. The selectivity with respect to the Q-aldehydes however, it is not particularly high because the catalyst system used has pronounced hydrogenating properties having. On the other hand, it is precisely in the case of the hydroformylation of propene to produce Ce alcohols necessary to interrupt the hydroformylation at the level of the C4 aldehydes, because only these easily and effectively condense to alcohols with twice the number of carbon atoms permit.

The possibility of hydroformylation of propene to n-butyraldehyde with high selectivity means hence a considerable technical advance in industrial production.

From DE-AS11 14 797 it was known that a Mixture of olefins, carbon monoxide and water in the presence of one of an iron carbonyl, an amine and water produced complex catalyst then in alcohols with a reduced proportion of Isoalcohols can be converted if one is involved in the preparation of the catalyst or during the synthesis process in addition to the amine, mono- or polybasic aliphatic, cycloaliphatic or nitriles aromatic carboxylic acids, lactams, carboxamides and / or lactones added. Due to the Differences in the processes, starting and end products and the special ones used similar behavior of a mixture of propene, carbon monoxide and hydrogen in the presence of one Cobalt carbonyls as a catalyst with respect to the catalysts could in no way be considered a Isomer distribution of the end product are closed.

Surprisingly, it has now been found that n-butyraldehyde is obtained with high selectivity can be, if one chooses a suitable solvent for the reaction; with this solvent should they are organic compounds with groups like

—CN or —CON

e.g. around Ν, Ν-dialkylamides, tetraalkyl ureas, aliphatic Act nitriles or aliphatic dinitriles; these compounds have 2 to 12 carbon atoms on. The following can be used with particular success: dimethylformamide, dimethylacetamide, Tetramethylurea, acetonitrile, adiponitrile etc. The C4 aldehydes that work when working in these solvents have ratios of normal to branched isomers in excess of 5.5: 1 and are of accompanied only small amounts of alcohol

The catalysts used are cobalt carbonyls, preferably through Lewis bases Phosphines, are substituted. In particular, you can trialkylphosphines with 2 to 8 carbon atoms in the Use alkyl groups, e.g. B. triethylphosphine, tri-n-butylphosphine, etc.

Examples of cobalt carbonyl complexes suitable for the reaction are:
[C (CO) (C) l

HCo (CO) iP (n-C4H ₉ ) 3] 2,

HcoCqP (nC ₄ H ₉ ) 3] 3,

[Co (CO) ₂ P (n-C4H ₉ ) 3] 2.

The catalyst can be formed in situ by adding soluble cobalt salts, phosphine and carbon monoxide reacts with each other. The amount of catalyst should be between 5 and 200 milliatoms of cobalt per liter Solvent lying. In practice it is preferable to work with concentrations of 60-80 miliatoms Cobalt per 1 solvent.

The reaction is carried out at temperatures between 110 and 220 ° C, preferably between 160 and 200 ° C carried out. The reaction pressure can be between 20 and 400 at; preferably one works at Printing between 40 and 210 at and in special cases between 90 and 120 at. The fed Gas mixture should contain the CO and the H2 in a preferred molar ratio.

The mechanism of the reaction is not entirely clear; however, it can be assumed that the Processes according to the invention, solvents used the structure of the added carbonyl complex modify considerably. In the table below are the absorption wavenumbers in the zone of carbonyls as well as the intensities of the IR bands of the reaction solution and - for comparison - of others Solutions that work under the same conditions but with different solvents (cf. Example 3) are compiled:

3 ν CO 1668 484 1950 cm- ' 4th 1890 cm- ¹ Dimethylformamide
Methyl isobutyl ketone
n-heptane 1990 or- ' no
weak
very strong very strong
strong
no weak
middle
no

The 1890 cm- 'gang consequently constitutes one is the characteristic value of the catalyst system when one of the solvents is used, which in the Within the scope of the present invention.

The following examples are provided for further explanation the invention.

example 1

A stainless steel shaking autoclave with a capacity of 200 cm ³ , which is equipped with a pressure measuring device (manometer), is carefully flushed with pure nitrogen.

Cobalt 2-ethylhexanoate
Tri-n-butylphosphine
Dimethylformamide
Propene

1.535 g (4.45 mM)
1.09 g (5.39mM)

60 cm ³
6.48 g (154.3 mM)

As soon as the temperature reaches 172 ^° C. (pressure = 19 at), the H2 — CO mixture is fed in in a volume ratio of 1: 1 until the total pressure is 45 at. The absorption of the gas starts immediately; the total pressure is kept between 45 and 40 atm by further feeding in the mixture. As soon as 64 atm of gas have been absorbed, the reaction is interrupted by cooling the autoclave.

The extracted gases are carefully measured and gas-volumetrically analyzed to determine the propane and propene content. The liquid is analyzed by gas chromatography at 100 ⁰ C to the content of Qs hydrocarbons, CU-alcohols, C 4 aldehydes and C "to determine alkyl formates; for this purpose an 8-m column was used, which was filled with diisodecyl phthalate on Chromosorb W (diatomaceous earth powder with a grain size of about 550 μ to 250 μ, manufactured and sold by the Johns-Manvil-Ie Corporation). The Ce-compounds were determined at 160 ⁰ C by means of a 4-m-column which 1540 (Poiyäthylenglykol the company Applied Science 'Laboratories, Inc.) was filled with Carbowax.

The withdrawn liquid and gaseous products contain 76.1 mM propene, 6.93 mM propane, 59.8 mM C ₄ aldehydes, 8.15 mM Gi alcohols and 0.28 mM C 4 alkyl formates.

Example 2

One works in the same way and with the same amount of the reactants as in Example 1 indicated and interrupts the reaction in each case at about 50-55%; there were three comparative tests with three different reaction media carried out The following table shows the dependence of the Selectivity with regard to the C4 aldehydes from the reaction medium in the hydroformylation of propene recognize:

Reaction medium Reaction time Selectivity on Moles of aldehydes Linear prod. Ci aldehydes Moles of alcohols branched Min. 0/0 Products Dimethylformamide 57 76.5 86 86.5 12th 13.5 Methyl isobutyl ketone • 18th 66.7 76.1 86.7 23.9 13.3 toluene 24 65.9 73.2 86.4 26.8 13.6 n-heptane 27 58.3 63.6 85.9 36.4 14.1

The reaction time (column 2) is the time in minutes that has _{elapsed between the introduction of the H 2} -CO mixture and the cooling of the autoclave. The molar amount of Q-aldehydes obtained from 100 mol of converted propene is given under selectivity (column 3). The ratio between linear and branched products (column 5) was calculated from the sum of alcohols + aldehydes.

Since the experiments only differ with regard to the reaction medium used, everything is clear It is clear from the table that the higher selectivity obtained in DMF (experiments of Example 1) is solely due to the use of this particular reaction medium.

Example 3

A stainless steel shaking autoclave with a capacity of 200 cm ³ , which is provided with a manometer, was carefully purged with pure nitrogen. Thereupon were fed:

[Co (CO) 3P (nC ₄ H ₉ ) 3] ₂
P (nC <H ₉ ) 3
HCO • N (CHi) ₂
Propene

2.525 g (3.66 mM) 1.785 g (8.83 mM) 100 cm ³ 10.6 g (252.4 mM)

After supplying the H ₂ -CO mixture (volume ratio 1: 1) until a total pressure of 68 at was reached,

the autoclave was ^{heated up to 180 °} C. The absorption of the gas begins at about 160 ^° C.; the total pressure is kept in the range from 11C to 100 atm by adding new mixture. After one hour the absorption is almost complete and the autoclave is cooled down.

The withdrawn products are analyzed as described in Example 1; the analysis showed: 41 mM Propene, 15.4 mM propane, 172 mM d-aldehydes, 18.26 mM graphic alcohols and 1.71 mM O-alkyl formates.

Selectivity to C ₄ aldehydes 81.3%

Moles of aldehydes / moles of alcohols 90.4 / 9.6
linear products / branched

Products 89.1 / 10.9

Example 4

The following was introduced into a 200 cm ³ autoclave, which was operated as described in Example 1:

2.53 g (3.66 mM)
1.785 g (8.85 mM)
100 cm ³

10.56 g (251.4 mM)

Tri-n-butylphosphine

NN-dimethylacetamide

CH ₃ -CO-N (CH ₃ J ₂

Propene

[Co (CO) ₃ P (nC ₄ H ₉ ) 3] 2
Tri-n-butylphosphine
Tetramethylurea
Propene

2.53 g (3.66 mM)
1.785 g (8.85 mM)
100 cm ³
10.78 g (256.6 mM)

10 obtained the following result: 32 ^ mM propene, 14.7 mM propane, 176 mM Q-aldehydes, 22.1 mM C-alcohols and 33 mM Q-alkyl formates.

Selectivity to C ₄ aldehydes 78.4%

Moles of aldehydes / moles of alcohols 88.8 / 11 2
linear products / branched

Products 89.5 / 10.5

Example 6

The procedure described in Example 1 was followed and the following products were ^{introduced into a 200 cm 3 autoclave:}

[Co (CO) ₃ P (nC ₄ H ₉ ) 3] 2
P (nC ₄ H ₉ ) ₃

CH ₃ -CN (acetonitrile)
Propene

After introducing the H ₂ CO mixture (volume ratio 1: 1) was achieved at up to a total pressure of 68 the autoclave was heated up to 180 ⁰ C. The absorption of the gas began at about 162 ° C; the total pressure was kept in the range of 110 to 100 atm by adding new mixture. After 34 minutes the absorption had dropped noticeably, whereupon the autoclave was cooled.

The withdrawn products were analyzed in the manner described in Example 1, the following result being obtained: 41.3 mM propene, 18.9 mM propane, 160.8 mM Ct-aldehydes, 22.8 mM C ₄ -alcohols and 1, 9 mM CV alkyl formates.

Selectivity to C ₄ aldehydes 76.5%

Moles of aldehydes / moles of alcohols 87.6 / 12.4
linear products / branched

Products 89.2 / 10.8

Example 5

The procedure was again as indicated in Example 1 and the following components were ^{introduced into a 200 cm 3 autoclave:}

2.53 g (3.66 mM)
1,785 g (8.83 mM)
100 cm ³
10.6g (252.4mM)

After introduction of the H2 CO mixture (volume ratio 1: 1) up to a total pressure of 138 at, the autoclave was heated to 180 ⁰ C. The absorption of the gas began at about 166 ° C a; the total pressure was kept in the range of 210 to 200 atm by adding new mixture. After 56 minutes the absorption had dropped noticeably, whereupon the autoclave was cooled. The withdrawn products were analyzed in the manner described in Example 1, the following result being obtained:

40.84 mM propene, 16.3 mM propane, 174.3 mM C ₄ aldehydes, 12.66 mM C ₄ alcohols and 3.5 mM formates.

Selectivity to C ₄ aldehydes 82.4%

Moles of aldehydes / moles of alcohols 93.2 / 6.8
linear products / branched

Products 87.1 / 12.9

35

Example 7

A shaking autoclave made of stainless steel with a capacity of 100 cm ³ , which was equipped with a manometer, was filled with the following components after careful flushing with pure nitrogen:

45 [Co (CO) ₃ P (nC ₄ H ₉ ) ₃ ] ₂
Tri-n-butylphosphine
Propionitrile, CH ₃ • CH ₂ CN
Propene

1.262 g (1.83 mM)
0.894 g (4.42 mM)
50 cm ³
5.32 g (126.7 mM)

After introduction of a H ₂ CO mixture (volume ratio 1: 1) up to a total pressure of 90 at, the autoclave was heated up to 175 ⁰ C. The absorption of the gas began at about 165 ° C; the eo total pressure was kept in the range of 130 to 120 atm by adding new mixture. After 32 minutes the absorption had dropped noticeably, whereupon the autoclave was cooled.

In the analysis of the withdrawn products, which was carried out in the manner described in b5 in Example 1, the autoclave was heated ^{to 178 °} _{C. after the H 2} —CO mixture had been fed in (volume ratio 1: 1) up to a total pressure of 133 atm . The absorption of the gas began at about 158 ° C; the total pressure was kept in the range of 210 to 200 atm by adding new mixture. After 50 minutes the autoclave was cooled. In the withdrawn product, which was analyzed in the manner described in Example 1, the following products were found: 28 mM propene, 7.3 mM propane, 79.8 mM C ₄ -AWehyde, 6.2 mM C ₄ -alcohols and 1 mM formates.

Selectivity to C ₄ aldehydes 80.8%

Moles of aldehydes / moles of alcohols 92.8 / 7.2
linear products / branched

Products 88.4 / 11.6

Claims (3)

Patent claims: 1. Process for the production of butyraldehydes by hydroformylation of propene in the presence of cobalt carbonyl-phosphine complex compounds, characterized in that the reaction medium used is a Ν, Ν-dialkylamide, a tetraalkylurea, £ in aliphatic nitrile or an aliphatic dinitrile having 2 to 12 carbon atoms is used 2. The method according to claim 1, characterized in that one works at a temperature between 110 and 220 ⁰ C and at CO + H2 pressures above 20 at and below 400 at 3. The method according to claim 1, characterized in that the reaction medium is dimethylformamide used