Hydroformylation method for the large-scale production of aldehydes and/or alcohols

Abstract

A process for preparing C.sub.4 to C.sub.13 monohydroxy compounds from a bottom fraction arising in the distillation of a crude mixture of C.sub.4 to C.sub.13 oxo-process aldehydes from cobalt-catalyzed or rhodium-catalyzed hydroformylation, or in the distillation of a crude mixture of C.sub.4 to C.sub.13 oxo-process alcohols, which comprises contacting the bottom fraction in the presence of hydrogen with a catalyst comprising copper oxide and aluminum oxide, at a temperature of 150° C. to 300° C. and a pressure of 20 bar to 300 bar and subjecting the resulting crude hydrogenation product to distillation, and the amount of C.sub.4 to C.sub.13 monohydroxy compounds present in the crude hydrogenation product after the hydrogenation being greater than the amount of C.sub.4 to C.sub.13 monohydroxy compounds given stoichiometrically from the hydrogenation of the ester and aldehyde compounds present in the bottom fraction, including the C.sub.4 to C.sub.13 monohydroxy compounds still present in the bottom fraction before the hydrogenation.

Claims

1. A process for preparing C.sub.4 to C.sub.13 monohydroxy compounds from a bottom fraction arising in the distillation of a crude mixture of C.sub.4 to C.sub.13 oxo-process aldehydes from cobalt-catalyzed or rhodium-catalyzed hydroformylation, or in the distillation of a crude mixture of C.sub.4 to C.sub.13 oxo-process alcohols, which comprises contacting the bottom fraction in the presence of hydrogen with a catalyst comprising copper oxide (CuO) and aluminum oxide, at a temperature of 180° C. to 260° C. and a pressure of 150 bar to 280 bar and subjecting the resulting crude hydrogenation product to distillation, and the amount of C.sub.4 to C.sub.13 monohydroxy compounds present in the crude hydrogenation product after the hydrogenation being greater than the amount of C.sub.4 to C.sub.13 monohydroxy compounds given stoichiometrically from the hydrogenation of the ester and aldehyde compounds present in the bottom fraction, including the C.sub.4 to C.sub.13 monohydroxy compounds still present in the bottom fraction before the hydrogenation.

2. The process according to claim 1, wherein the catalyst comprises copper oxide (CuO) with a fraction of 40 to 80 weight percent, aluminum oxide with a fraction of 5 to 60 weight percent, and 0 to 30 weight percent of manganese oxide (MnO), lanthanum oxide or zinc oxide, the weight percentages are based on the total weight of the oxidic material present in the catalyst after calcining, the sum of the weight fractions adds up to 90 to 100 percent, and the fraction of oxidic material in the catalyst is at least 80 weight percent, based on the total weight of the catalyst after calcining.

3. The process according to claim 1, for producing C.sub.4 to C.sub.9 monohydroxy compounds from a bottom fraction arising in the distillation of a crude mixture of C.sub.4 to C.sub.9 oxo-process aldehydes from cobalt-catalyzed or rhodium-catalyzed hydroformylation, or in the distillation of a crude mixture of C.sub.4 to C.sub.9 oxo-process alcohols.

4. The process according to claim 3, for producing n-butanol and/or isobutanol from a bottom fraction arising in the distillation of a crude mixture of C.sub.4 oxo-process aldehydes from rhodium-catalyzed hydroformylation, or in the distillation of a crude mixture of C.sub.4 oxo-process alcohols.

5. The process according to claim 1, wherein the bottom fraction, before being contacted with hydrogen and a catalyst, is subjected to extraction, distillation or stripping.

6. The process according to claim 1, wherein the bottom fraction, before being contacted with hydrogen and a catalyst, is subjected to extraction and distillation.

7. The process according to claim 1, wherein a part of the crude hydrogenation product obtained from the hydrogenation is returned to the disclosed process and a part of the crude hydrogenation product obtained from the hydrogenation is subjected to distillation.

8. A process for preparing C.sub.4 monohydroxy compounds by hydrogenolysis of C.sub.8 diols, which comprises contacting C.sub.8 diols in the presence of hydrogen with a catalyst comprising copper oxide and aluminum oxide, at a temperature of 150° C. to 300° C. and a pressure of 20 bar to 300 bar, reacting the C.sub.8 diols at least partially to give C.sub.4 monohydroxy compounds, and subjecting the resulting crude C.sub.8 diol hydrogenation product to distillation.

9. A process for preparing C.sub.4 monohydroxy compounds from the bottom fraction arising in the distillation of a crude mixture of C.sub.4 oxo-process aldehydes from rhodium-catalyzed hydroformylation or in the distillation of a crude mixture of C.sub.4 oxo-process alcohols, which comprises contacting the bottom fraction in the presence of hydrogen with a catalyst comprising copper oxide and aluminum oxide, at a temperature of 150° C. to 300° C. and a pressure of 20 bar to 300 bar and subjecting the resulting crude hydrogenation product to distillation, and the amount of n-butanol, isobutanol or a mixture thereof present in the crude hydrogenation product after the hydrogenation being greater than the amount of n-butanol, isobutanol or a mixture thereof given stoichiometrically from the hydrogenation of the ester and aldehyde compounds present in the bottom fraction, including the C.sub.4 monohydroxy compounds still present in the bottom fraction before the hydrogenation.

Description

EXAMPLES

(1) The examples are intended to serve to illustrate the present invention and not to have any restrictive character thereon.

(2) In all of the examples, hydrogen was used in an excess of 120% to 160%, based on the amount needed stoichiometrically for the hydrogenation and/or hydrogenolysis of the reactants.

(3) The potassium and phosphorus contents were determined by elemental analysis (atomic absorption spectroscopy).

(4) The ester number was determined in analogy to EN ISO 3681.

(5) The acid number was determined in analogy to EN ISO 2114.

(6) The calculation of the yield of C.sub.4 to C.sub.13 monohydroxy compounds obtained from a bottom fraction by means of the process of the invention will be shown by way of example below for n-butanol and isobutanol as the C.sub.4 monohydroxy compounds.

(7) In a first step, the bottom fraction passed to the process of the invention is analyzed to determine whether the components it contains can be traced back formally to C.sub.4 or C.sub.8 constituents. The analysis is conducted by GC, the retention times of the individual compounds having been elucidated by GC/MS.

(8) The components present in the bottom fraction are then classed as follows.

(9) Isobutanol: 100% C.sub.4

(10) n-Butanol: 100% C.sub.4

(11) n-Butyl butyrate: 100% C.sub.4

(12) n-Butyraldehyde n,n-dibutyl acetal: 100% C.sub.4

(13) C.sub.8 diols: 100% C.sub.8

(14) 2-Ethylhexan-1-ol: 100% C.sub.8

(15) C.sub.12 esters: 33% C.sub.4, 67% C.sub.8

(16) Thus, for example, isobutanol, n-butanol, n-butyl butyrate, n-butyraldehyde n,n-dibutyl acetal are traced back formally 100% to C.sub.4 constituents. C.sub.8 diols and 2-ethylhexan-1-ol, for example, are traced back formally 100% to C.sub.8 constituents. C.sub.12 esters for example are traced back formally 33% to C.sub.4 and 67% to C.sub.8 constituents.

(17) By summing the components it is possible to determine a C.sub.4 fraction, a C.sub.8 fraction, and a fraction of unapportioned components in the feed. The total of n-butanol and isobutanol which is obtained in the discharge is the total C.sub.4 yield.

(18) On the assumption that the conversion of the C.sub.4 components in the feed to n-butanol and isobutanol is complete, the figure for the total C.sub.4 yield in the discharge can be used to calculate the conversion of the C.sub.8 components as follows:
Total C.sub.4 yield−C.sub.4 fraction in the feed−fraction of unapportioned components in the feed=yield through conversion of C.sub.8 components to C.sub.4 components through conversion of C.sub.8 components.

(19) By means of this method of calculation it is possible to ascertain how many C.sub.8 components are converted into n-butanol and isobutanol. The composition of the discharge is likewise determined by means of GC, the retention times of the individual compounds having been elucidated by GC/MS.

(20) The percentages of the individual components are based on GC area percent.

Example 1

(21) The discharge of rhodium-catalyzed hydroformylation was separated by rectification into n-butyraldehyde and isobutyraldehyde. The n-butyraldehyde thus obtained was passed to a hydrogenation, and the discharge of the hydrogenation was separated by rectification. The bottom fraction arising in this rectification was used as reactant.

(22) Reactant Composition:

(23) 3% n-Butanol

(24) 3% n-Butyln-butyrate

(25) 9% n-Butyraldehyde n,n-dibutyl acetal

(26) 47% C.sub.8 diols

(27) 12% Ethylhexan-1-ol

(28) 21% C.sub.12 esters

(29) 5% Others

(30) 500 mg/kg Potassium

(31) 100 mg/kg Phosphorus

(32) 0.01% Water

(33) Ester number of reactant 76 mgKOH/g.

(34) C.sub.4 fraction of feed: 22%

(35) C.sub.8 fraction of feed: 73%.

(36) The reactant was mixed with hydrogen in excess and the mixture was passed in trickle mode over a reactor filled with a catalyst, comprising 24 wt % aluminum oxide, 72 wt % copper oxide (CuO), and 4 wt % lanthanum oxide, based on the total weight of the catalyst after calcining, at 240° C., at a pressure of 200 bar, and with a catalyst loading of 0.32 g.sub.reactant/(ml.sub.catalyst×h).

(37) Discharge Composition:

(38) 44% n-Butanol

(39) 10% Isobutanol

(40) 14% 2-Ethylhexan-1-ol

(41) 32% Others

(42) 220 mg/kg Potassium

(43) 28 mg/kg Phosphorus

(44) Ester number of discharge: 4 mgKOH/g,

(45) Total C.sub.4 yield: 54%.

(46) Yield by conversion of C.sub.8 components to C.sub.4 components: 27%,

(47) Percentage conversion of C.sub.8 to C.sub.4 components: 37%.

Example 2

(48) The discharge from the rhodium-catalyzed hydroformylation of propene was separated by rectification into n-butyraldehyde and isobutyraldehyde. The n-butyraldehyde thus obtained was passed to a hydrogenation, and the discharge from the hydrogenation was separated by rectification. The bottom fraction arising in this rectification was used as reactant. In comparison to example 1, the reactant was additionally extracted with 3×20 wt % of demineralized water, based on the weight of the reactant. The organic phase was mixed with an excess of hydrogen and the mixture was passed in trickle mode over a reactor filled with a catalyst, comprising 24 wt % aluminum oxide, 72 wt % copper oxide (CuO) and 4 wt % lanthanum oxide, based on the total weight of the catalyst after calcining, at 240° C., at a pressure of 200 bar, and with a catalyst loading of 0.32 g.sub.reactant/(ml.sub.catalyst×h).

(49) Discharge Composition:

(50) 49% n-Butanol

(51) 11% Isobutanol

(52) 16% 2-Ethylhexanol

(53) 24% Others

(54) 130 mg/kg Potassium

(55) 28 mg/kg Phosphorus

(56) Ester number of discharge: 7 mgKOH/g.

(57) Total C.sub.4 yield: 60%.

(58) Yield by conversion of C.sub.8 components to C.sub.4 components: 33%.

(59) Percentage conversion of C.sub.8 to C.sub.4 components: 45%.

(60) By extracting the bottom fraction with water it is possible to reduce the potassium fraction in the discharge and to increase the total yield and therefore the conversion of C.sub.8 components to C.sub.4 components.

Example 3

(61) The discharge from the rhodium-catalyzed hydroformylation of propene was separated by rectification into n-butyraldehyde and isobutyraldehyde. The n-butyraldehyde thus obtained was passed to a hydrogenation, and the discharge from the hydrogenation was separated by rectification. The bottom fraction arising in this rectification was used as reactant. The reactant was distilled on a falling-film evaporator. The distillate was collected.

(62) Reactant Composition:

(63) 4% Butanol

(64) 9% n-Butyl n-butyrate

(65) 1% n-Butyraldehyde n,n-dibutyl acetal

(66) 55% C.sub.8 diols

(67) 12% 2-Ethylhexan-1-ol

(68) 18% C.sub.12 esters

(69) 1% Others

(70) 470 mg/kg Potassium

(71) 75 mg/kg Phosphorus

(72) Ester number of reactant: 86 mgKOH/g.

(73) Distillate Composition:

(74) 4% n-Butanol

(75) 8% n-Butyl n-butyrate

(76) 1% n-Butyraldehyde n,n-dibutyl acetal

(77) 55% C.sub.8 diols

(78) 12% 2-Ethylhexan-1-ol

(79) 18% C.sub.12 esters

(80) 1% Others

(81) <3 mg/kg Potassium

(82) 84 mg/kg Phosphorus

(83) Ester number of distillate: 84 mgKOH/g.

Example 4

(84) A reactant distilled as in example 3 was used.

(85) Reactant Composition after Distillation:

(86) 2% n-Butanol

(87) 7% n-Butyl n-butyrate

(88) 2% n-Butyraldehyde n,n-dibutyl acetal

(89) 58% C.sub.8 diols

(90) 13% 2-Ethylhexan-1-ol

(91) 18% C.sub.12 esters

(92) <1% Others

(93) <1 mg/kg Potassium

(94) 5 mg/kg Phosphorus

(95) Ester number of reactant: 87 mgKOH/g.

(96) C.sub.4 fraction in reactant: 17%.

(97) C.sub.8 fraction in reactant: 83%.

(98) The reactant was mixed with hydrogen and a portion of the discharge, and this mixture was passed in trickle mode over a reactor filled with a catalyst, comprising 24 wt % aluminum oxide, 72 wt % copper oxide (CuO), and 4 wt % lanthanum oxide, based on the total weight of the catalyst after calcining, at 240° C., at a pressure of 175 bar, and with a catalyst loading of 0.32 g.sub.reactant/(ml.sub.catalyst×h). A portion of the discharge was mixed with the reactant so as to give a total liquid hourly space velocity over the catalyst of 4.7 g.sub.liquid/(ml.sub.catalyst×h). A portion of the discharge is accordingly returned to the reactor in a circular regime.

(99) Discharge Composition:

(100) 39% n-Butanol

(101) 10% Isobutanol

(102) 16% 2-Ethylhexan-1-ol

(103) 35% Others

(104) <3 mg/kg Potassium

(105) 4 mg/kg Phosphorus

(106) Ester number of discharge: 14 mgKOH/g.

(107) Total C.sub.4 yield: 49%.

(108) Yield through conversion of C.sub.8 components to C.sub.4 components: 32%.

(109) Percentage conversion of C.sub.8 to C.sub.4 components: 39%.

(110) TABLE-US-00001 TABLE 1 Overview of the result of examples 1, 2 and 4 Reactant Products C.sub.4 C.sub.8 Un- C.sub.4 C.sub.8 Ex- com- com- com- com- com- Un- ample ponents ponents ponents ponents ponents known 1 22% 73% 5% 54% 14% 32% 2 22% 73% 5% 60% 16% 24% 4 17% 83% 0% 49% 16% 35%

Example 5

(111) Reactant Composition:

(112) 8% n-Butanol

(113) 60% C.sub.8 diols

(114) 6% 2-Ethylhexan-1-ol

(115) 18% C.sub.12 esters

(116) 8% Others

(117) 215 mg/kg Potassium

(118) 13 mg/kg Phosphorus

(119) Ester number of reactant: 71 mgKOH/g.

(120) Acid number of reactant: 7 mgKOH/g.

(121) C.sub.4 fraction of reactant: 14%.

(122) C.sub.8 fraction of reactant: 78%.

(123) The reactant was mixed with hydrogen and the mixture was passed in liquid-phase mode over a reactor filled with a catalyst, at 220° C., at a pressure of 175 bar, and with a catalyst loading of 3.3 g.sub.liquid/(ml.sub.catalyst×h). The reactant stream was mixed with a partial stream composed of the discharge in a ratio of 1:10, and this mixture was supplied to the reactor. Hydrogen was supplied to the combined stream in excess.

(124) Catalysts used were as follows:

(125) The figures for weight percent are based on the total weight of the catalyst after calcining.

(126) TABLE-US-00002 Copper Manganese Aluminum oxide Lanthanum Zinc oxide oxide (CuO) oxide oxide (MnO) Bulk Catalyst wt % wt % wt % wt % wt % density 1 30 60 10 1.31 g/ml 2 24 72 4 1.21 g/ml 3 51 49 0.87 g/ml 4 5 70 25 1.32 g/ml

(127) Table 2 below reports the compositions of the respective discharge with the corresponding catalyst. As can be seen from the table, the use of catalyst 2 leads to initially high butanol yields (54.2%) and high ester conversion. The other catalysts, especially catalyst 1, do lead to lower butanol yields, but fewer middle-boiling byproducts (sum total of dibutyl ether and others) are formed. The total C.sub.4 yield through conversion of C.sub.8 components is predominantly greater than 20% and amounts to up to 40%. The relative conversion of C.sub.8 to C.sub.4 components amounts to up to 74%.

(128) On the basis of the ester number and acid number, maximum butanol yields of 19.7% are possible, on the assumption of the complete hydrogenation of the ester functions of n-butyl and/or isobutyl butyrate and of the complete hydrogenation of butyric acid.

(129) TABLE-US-00003 TABLE 2 Composition of the discharge for different catalysts Total C4 yield % Ester Acid through Con- 2- Buta- number number con- version Ethyl- nol/ (stand- (stand- version of C8 Tem- n- Iso- hex- Di- Buta- by- ard) ard) of C8 to C4 K P Run pera- Bu- bu- ane- butyl C8 C12 nol prod- mg mg com- com- con- con- Cata- time ture tanol tanol 1-ol ether diols esters Others yield ucts (KOH)/ (KOH)/ ponents ponents tent tent lyst h ° C. % % % % % % % % — g g % % ppm ppm 1 170.5 200 41.1 15.8 6.9 2.6 18.2 3.0 12.4 49.0 7.2 13 0 34.9 71.3% 140 7 479.2 200 30.5 11.7 7.3 2.1 30.6 4.9 12.9 34.3 5.0 19 0 20.2 59.0% 190 8 569.2 210 35.9 15.1 8.0 3.3 17.4 3.7 16.6 43.0 3.7 20 0 29.0 67.3% n.d. n.d. 975.45 200 18.9 7.3 7.1 1.3 42.8 9.6 12.8 18.3 3.1 41 0 4.2 23.1% n.d. n.d. 2 160.5 200 43.3 18.9 7.4 3.3 9.6 0.5 17.0 54.2 4.5 0 0 40.2 74.1% 85 7 497.5 200 34.4 15.1 8.5 3.4 18.3 0.7 19.5 41.6 2.8 4 0 27.5 66.2% 175 8 574 210 38.2 17.8 8.7 4.0 9.2 0.5 21.6 48.1 2.8 2 0 34.0 70.8% n.d. n.d. 976 200 30.4 14.0 8.0 3.4 24.3 1.5 18.4 36.5 2.7 10 0 22.5 61.5% n.d. n.d. 3 160.5 200 31.5 13.5 9.4 2.2 18.7 1.7 23.0 37.1 2.2 6 0 23.0 62.1% 18 5 497.5 200 30.5 13.2 9.0 3.1 21.7 2.0 20.5 35.8 2.3 8 0 21.8 60.8% 160 6 574 210 34.4 16.1 9.4 3.9 11.4 1.2 23.5 42.6 2.2 7 0 28.6 67.0% n.d. n.d. 970.5 200 27.8 13.1 8.4 3.3 25.6 2.5 19.3 32.9 2.3 13 0 18.9 57.4% n.d. n.d. 4 160.5 200 30.6 13.7 10.3 3.7 14.2 0.5 26.9 36.4 1.6 0 0 22.3 61.4% 150 7 497.5 200 29.1 12.6 10.0 3.8 18.8 0.8 24.8 33.8 1.7 5 0 19.7 58.4% 195 7 574 210 31.5 14.9 10.2 4.4 10.8 0.7 27.6 38.4 1.6 3 0 24.4 63.4% n.d. n.d. 976 200 25.6 11.9 9.2 3.9 24.3 1.6 23.6 29.5 1.5 10 0 15.5 52.4% n.d. n.d. Feed — — 7.9 0.0 5.5 0.0 59.9 18.4 8.2 — — 71 7 — — 215 13

(130) The feed already contains around 8% of butanols. These are subtracted from the total of the n-butanols and isobutanols to determine the amount of n-butanols and isobutanols newly formed during the reaction.

Example 8

(131) 2 g of a catalyst containing 24 wt % aluminum oxide, 72 wt % copper oxide, and 4 wt % lanthanum oxide, based on the total weight of the catalyst after calcining, were charged to an autoclave and activated under hydrogen pressure. Then 100 g of 2-ethylhexane-1,3-diol were added, and the contents were maintained under a hydrogen pressure of 175 bar at 220° C. for 8 hours. Samples were taken from the liquid phase of the reactor and were analyzed by gas chromatography. The results obtained were as follows:

(132) TABLE-US-00004 Time Yield of 2-ethylhexane- Yield of n- in hours 1,3-diol in % butanol in % 0 100 0 2 62 17 5 27 32 8 12 38

Example 9

(133) The discharge from the cobalt-catalyzed hydroformylation of isooctene was separated from the hydroformylation catalyst and then passed to a hydrogenation, and the discharge from the hydrogenation was separated by rectification. The bottom fraction arising in this rectification was used as reactant. The reactant was analyzed as follows:

(134) 1% Isononanol

(135) 99% High boilers

(136) Ester number of reactant: 55 mgKOH/g.

(137) Acid number of reactant: 12 mgKOH/g.

(138) The reactant was mixed with hydrogen in excess and this mixture was passed in trickle mode over a reactor filled with a catalyst containing 24 wt % aluminum oxide, 72 wt % copper oxide (CuO), and 4 wt % lanthanum oxide, based on the total weight of the catalyst after calcining, at 200° C., at a pressure of 200 bar, and with a catalyst loading of 0.3 g.sub.reactant/(ml.sub.catalyst×h).

(139) The discharge was analyzed as follows:

(140) 32% Isononanol

(141) Ester number of discharge: 17 mgKOH/g.

(142) Acid number less than 1 mgKOH/g.

(143) The hydrogenation of the acid formed about 3.5% of isononanol, and the hydrogenation of the ester 19% of isononanol. In total, however, 31% of isononanol was formed, thus indicating the conversion of other high boilers.