Ind. Eng. Chem. Res. 1995,34, 971-973
971
Process for Manufacturing 1,4=Butanediolfrom Acrolein Shuji Ichikawa, Yuji Ohgomod,* Naoko Sumitani, Hideto Hayashi, and Makoto Imanari* Tsukuba Research Center, Mitsubishi Petrochemical Co., Ltd., 8-3-1 Chuou, Ami,Zbaraki 300-03, Japan
1,4-Butanediol was obtained in high yield by hydroformylation of acrolein acetal in the presence of the Rh-diphosphine catalysts, followed by subsequent hydrolysidhydrogenation of the products over Ru and heteropolyacid catalysts supported on carbon. 2,3-O-Isopropylidene-2,3-dihydroxy1,4-bis(diphenylphosphino)butane was found to be a highly efficient ligand in the above hydroformylation reaction to produce the desired intermediate to 1,4-butanediol. Preliminary cost evaluation revealed t h a t the method presented in this paper is promising for industrial application.
Introduction 1,4-Butanediol (1,4-BDO) is an important precursor for polybutylene terephthalate (PBT), which has many interesting properties as one of the high performance engineering plastics. 1,4-BDO is now mainly manufactured by the reaction of acetylene and formaldehyde, followed by catalytic hydrogenation of the resulting 1,4butynediol. Other methods to produce 1,4-BDO have been proposed (Brownstein and List, 1977). Acrolein, which can be obtained in high yield by oxidation of propene, has been proposed for use as the raw material in the production of 1,4-BDO as shown in Scheme 1 (Hughes, 1977). However, further development of this route is at present abandoned because of economic reasons. The major disadvantage of this route is the formation of branch isomer 5 along with the desired linear isomer 4 particularly at low catalyst concentrations. Many patents describe the use of catalysts composed of RhP(ORh (R = alkyl or aryl) or Rh-PPhs in the hydroformylation step (Botteghi and Soccolini, 1985). Since phosphites P(OR)3 in the former system are relatively unstable under the reaction conditions, this catalyst system cannot be used industrially. In this paper, we wish t o report a way of improving the reaction rate for the formation of 4 with high selectivity by using diphosphines as the ligand in rhodium catalysts.
Scheme 1. Synthesis of 1,4Butanediol from Acrolein ecno
The acrolein acetal 3 was obtained by the reaction of acrolein (1) and 2-methyl-l,3-propanediol(2) in a 1:1.5 molar ratio by being passed through a 6 mm diameter x 200 mm length column packed with sulfonated ion exchange resin at 10 "C, and a t a LHSV (liquid hourly space velocity on acrolein) of 10 h-l. Selectivity t o acrolein acetal 3 was 96% at 89% conversion of acrolein. Pure 3 can be obtained by fractional distillation. Recently, Casey et al. described the role of disphosphines in the hydroformylation of 1-hexene catalyzed by Rh (Casey et al., 1992). They observed that selectivity to a linear aldehyde can be correlated with the calculated natural bite angle of a diphosphine-Rh complex and that the maximum selectivity was obtained by using BISBI as a ligand with a bite angle of 112.6'. We have examined Rh-catalyzed hydroformylation of substrate 3 using several kinds of diphosphine ligands including BISBI, T-BDCP, DIOP, and DIPHOS which were used in Casey's work. The diphosphine ligands are illustrated in Scheme 2, and results are summarized in Table 1,together with the n l i ratio of the aldehydes
no> no
H'
21
2
1
3
cno
5
4
Scheme 2. Structure and Abbreviations of Phosphine Ligands PPhz
ogh;:: H
norbonyl
PPhz %:LPPhz H
DIOP
Results and Discussion
t
BlSBl
T-BDCP
8
'-$PPhz PPhz
P
h
Z
,, PPh2 \
MDlOP
P
CHDIOP
PPhz 'PPh2
\
BINAP
DIPHOS
obtained by hydroformylation of 1-hexene in Casey's work. Under the conditions noted in footnote a in Table 1,the highest conversion and selectivity were unexpectedly obtained by DIOP (bite angle, 102.2")using acrolein acetal 3 as the substrate. Diphosphine BISBI, which is the most efficient ligand in the hydroformylation of 1-hexene reported by Casey et al. (under the different reaction conditions: BISBI/Rh,l; 1-hexenekh, 645; temperature, 33.6 "C; pressure, 500 m a ) , exhibits low conversion and selectivity, while hydrogenated acrolein acetal was obtained with 62.8% selectivity. In the next step, we tried to reduce the rhodium concentration using some diphosphines (Table 1, entries 4, 6, and 8). Reaction conditions such as the molar ratio of ligand Rh, reaction temperature, and pressure were optimized for desired 4 formation. In all cases, high rates of conversion were obtained even at 8 ppm of Rh ([Rhl, 0.001 mol %), and the highest selectivity was observed using T-BDCP. Unfortunately, T-BDCP is relatively unstable under the hydroformylation conditions, so CHDIOP is the best ligand under these reaction conditions for practical application. The Rh-PPhs system,
0888-588519512634-0971$09.0OlO 0 1995 American Chemical Society
972 Ind. Eng. Chem. Res., Vol. 34, No. 3, 1995 Table 1. Effect of Various Phosphine Ligands in Hydroformylation of Acrolein Acetala acrolein acetal % selectivityd
%
entry 1 2
3
phosphineb L norbonyl BISBI T-BDCP
calculated bite angle for L-Rh/deg' 126.1 112.6 106.6
4g
5
CHDIOP
gs
7
DIOP
102.2
8g
9 10
11 1%
MDIOP BINAPh DIPHOS PPh3
90.6i 84.5
conversion
4
+5
6
4/5'
13.5
14.3
62.8
1.13
100 99.4 99.0 99.9 100 41.2 16.8 38.0 0.6
97.7 99.2 97.4 99.1 96.4 95.9 90.3 92.6 49.1
2.2 0.7 2.4 0.8 2.1 0.5
7.48 3.83 5.82 5.11 4.68 1.13 0.75 0.30 2.20
0.1
l-hexenec ratef n/ie 9.3 29.4 3.7
2.9 66.5 12.1
6.4
8.5
1.1
2.1
Reaction conditions: [Rhl, 0.005 mol %; L"Rh, 2 mol/g atom; CO/Hz ( W , 1000 KPa; 100 "C, 2 h. See Scheme 1. Data taken from e Mol linear aldehyddmol branch Casey et al., 1992. [mol productlmol acrolein acetal converted] x 100. 6 2-Ethyl-5-methyl-l,3-dioxane. aldehyde. f [Mol aldehydel.[mol Rhl-l'h-'. Reaction conditions: [Rhl, 0.001 mol %; m h , 10 moVg atom; CO/H2 (l/l),200 KPa; 110 "C; 4 h. WRh, 200 moVg atom. Observed value for BINAP-Ru; Ohta et al., 1988.J Reaction conditions: [Rh], 0.001 mol %; WRh, 200 moVg atom; CO/Hz (l/l), 200 KPa; 110 "C; 4 h. Table 2. Reuse of Hydroformylation Catalystsa entry
reuse
% conversion
% yield of 4
4/5
13 14b 15b 16b
fresh first second third
99.4 97.8 99.5 99.8
81.6 84.4 86.3 87.8
4.42 4.83 5.31 6.35
a Reaction conditions: [Rhl, 0.001 mol %; WRh, 10 moVg atom; CO/Hz (l/l), 200 KPa; 110 "C; 4 h. Residue obtained by distillation of the reaction solution in previous runs (still, 90 "C; 13 Pa; 40 min) was reused as the catalyst.
Table 3. HydrolysidHydrogenation of a Mixture of 4 and 5'"
selectivity at very low catalyst concentrations compared to previous reports, and the catalysts are reusable; (2) succinaldehyde monoacetal converts into 1,4-BDO in almost quantitative yield in the neutral medium in the presence of Ru and heteropolyacid catalysts supported on carbon; (3) the overall yield of 1,4-BDO reaches ca. 79% based on acrolein. We also conducted a preliminary economical evaluation on the basis of the above results. It revealed that the present process at this stage is competitive compared with the other industrial methods (Matsumoto et al., 1985; Sharif and Turner, 1985; Toriya et al., 1975).
% yieldb
entry 17
MC 1gC 20' 2lC
reuse fresh first second third fourth
1,4-BDO 96.5 96.9 97.2 97.4 98.1
n-PrOH 2.2 1.8 1.8 1.6 1.4
n-BuOH trace 0.5 0.5 0.6 0.5
THF 1.4 0.8 0.6 0.6 trace
Reaction conditions: 4/5,26 mmol; 5 % Ru + 5 % H4SiW12040 on carbon, 0.2 g; Hz, 7 MPa; 100 "C; 4 h. Based on 4. Catalyst was recovered by filtration at the end of the previous run and reused. a
which has been used in previous works (Hughes, 1977) affords extremely low conversion and selectivity a t 8 ppm of Rh (Table 1, entry 12). We have tried to reuse the catalyst system. After the hydroformylation reaction of 3 in the presence of RhCHDIOP catalysts, the volatile products were distilled from the reactor at reduced pressure (still, 90 "C; 13 Pa; 40 min). Fresh 3 was added to the residue and exposed to CO/H2. This procedure was repeated three times. The results are presented in Table 2, which reveals that the Rh-CHDIOP catalyst system is potentially reusable. The product ratio of 4/5 increases with repeated use of catalysts, but the reason is not yet clear. The aldehyde 4 in the product mixture obtained by the above hydroformylation reaction reacted with HzO and H2 to afford 1,4-BDO in almost quantitative yield in the presence of 5 wt % Ru and 5 wt % H4SiW12040 catalysts supported o n carbon. The catalysts are recoverable by simple filtration and are reusable as shown in Table 3.
Conclusions To conclude: (1)the rate to form the desired succinaldehyde monoacetal is greatly improved with high
Experimental Section Acetylacetonatodicarbonylrhodium (N. E. Chemcat) was used as the catalyst precursor. Diphosphines DIOP, BINAP, and DIPHOS were purchased from Strem. The other diphosphines used in this work were prepared according to literature methods: BISBI, Devon et al., 1987; T-BDCP, Aviron-Violet et al., 1979; CHDIOP and MDIOP, Napolitano et al., 1986; Kagan and Dank, 1972. Hydrolysishydrogenation catalysts were prepared as follows. An aqueous solution of the heteropolyacid was added to 5 % Ru-C powder (N. E. Chemcat) and dried. The catalyst was washed with water in a Soxhlet extractor for 13.5 h and dried in vacuo. All reactions were run in a 50 cm3 autoclave constructed of stainless steel with heating and agitation means. COM2 and H2 were maintained at constant pressures during reactions by means of pressure control valves. Analyses of the reaction products were performed by GC. Acknowledgment We thank Miss Akiko Fujita of our laboratory for her helpful experimental assistance. Thanks are due to Mr. Masashi Inaba and Mr. Shiro Inui a t Yokkaichi Research Center of MPC for their works on the economical evaluation, and approval for publication of this work by Mitsubishi Petrochemical Company is gratefully acknowledged. Literature Cited Aviron-Violet, P.; Colleuille, Y.; Varagnat, J. Hydrogenation Asymetrique en presence de Diphosphines Chirales. J . Mol. Cutal. 1979, 5, 41.
Ind. Eng. Chem. Res.,Vol. 34, No. 3, 1995 973 Botteghi, C.; Soccolini, F. Malonaldehyde, succinaldehyde, and glutaraldehyde monoacetals: Syntheses and applications. Synthesis 1986, 592 and references cited therein. Brownstein, A. M.; List, H. L. Which route to 1,4-butanediol? Hydrocarbon Process. 1977, 56 (Sept), 159. Casey, P. C.; Whiteker, G. T.; Melville, M. G.; Petrovich, L. M.; Gavney, J. A.; Powell, D. R. Diphosphines with natural bite angle near 120" increase selectivity for n-aldehyde formation in rhodium-catalyzed hydroformylation. J . Am. Chem. SOC. 1992,114,5535. Devon, T. J.; Phillips, G. W. Chelate Ligands for Low Pressure Hydroformylation Catalyst and Process Employing Same. US. Patent 4694109, 1987. Hughes, 0. R. Production of 2-vinyl-l,3-dioxane compounds. U.S. Patent 4003918, 1977. Kagan, H. B.; Dang, T. P. Asymmetric Catalytic Reduction with Transition Metal Complexes. 1. A Catalytic System of Rhodium(1) with (-)-2,3-O-Isopropylidene-2,3-dihydroxy-l,4-bis(diphenylphosphino)butane,a New Chiral Diphosphine. J . Am. Chem. SOC.1972,94,6429.
Matsumoto, M.; Miura, S.; Kikuchi, K.; Tamura, M.; Kojima, H.; Koga, K.; Yamashita, S. Continuous hydroformylation of allyl alcohol. Eur. Patent 129802, 1985. Napolitano, E.; Fiaschi, R.; Mastrorilli, E. Halogenative Deoxygenation of Ketones. Synthesis 1986, 122. Ohta, T.; Takaya, H.; Noyori, R. BINAP-Ruthenium(I1) Dicarboxylate Complexes: New, Highly Efficient Catalysts for Asymmetric Hydrogenation. Znorg. Chem. 1988,27, 566. Sharif, M.; Turner, K. Butane-1,4-diol preparation. Eur. Patent 143634, 1985. Toriya, J.;Shiraga, K.; Onoda, T.; Ohno, A. Diacetoxybutane. Ger. Offen 2513522,1975.
Received for review August 8 , 1994 Accepted November 16, 1994@ IE940477H ~~
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Abstract published in Advance ACS Abstracts, February 1, 1995. @
