4. Production
Dehydrogenation of 1,4-Butanediol [110-63-4] (® Butanediols, Butenediol, and Butynediol). The Reppe process for manufacturing butyrolactone involves the endothermic dehydrogenation of 1,4-butanediol in the gas phase. This process is used by BASF, ISP, and Lyondell.
Preheated 1,4-butanediol vapor is introduced into a hot stream of circulating hydrogen and passed at atmospheric pressure through a bed of copper catalyst at temperatures between 180 and 240 °C (Figure (1)). The yield of butyrolactone is approximately 95 %. The reaction takes place via g-hydroxybutyraldehyde [25714-71-0] [7].
The byproduct hydrogen off-gas requires only simple purification before reuse (e.g., catalytic methanization of carbon monoxide impurities). The crude butyrolactone separated from the recycle gas stream contains small amounts of byproducts, including 1,4-butanediol, butyric acid, and high boilers, from which butyrolactone is separated by distillation.
Butyrolactone itself is noncorrosive and can be handled in carbon steel apparatus. However, where parts of the synthesis or distillation vessels and pipes come into contact with hot crude product containing butyric acid, they must be made of stainless steel.
Hydrogenation of Maleic Anhydride [108-31-6]. In the preparation of butyrolactone by hydrogenating maleic anhydride, molten maleic anhydride is fed into a preheated circulating stream of hydrogen and passed under a pressure of 6 – 12 MPa at 160 – 280 °C over a nickel-containing catalyst [8].
The reaction takes place via succinic anhydride [108-30-5] and can, by choice of the conditions, be continued to produce tetrahydrofuran [109-99-9]. The excess hydrogen is washed with water and recycled to the synthesis. Byproducts contained in the butyrolactone are separated out of the circulating gas: propanol [71-23-8], butanol [71-36-3], propionic acid [79-09-4], and butyric acid [107-92-6]. The butyrolactone is separated from these by distillation.
Because of the acids present, both the synthesis apparatus and the distillation apparatus must be made of stainless steel. The Japanese manufacturer Mitsubishi Chemical Corporation [9] uses this process.
Hydrogenation of Maleic Esters. New processes for the production of 1,4-butanediol and tetrahydrofuran starting from maleic anhydride via dimethyl maleate have been developed in the past few years (® Tetrahydofuran). They offer the possibility of extracting butyrolactone, which is an intermediate in these processes.
In a process developed by Kvaerner Process Technology (KPT, London) [10] dimethyl maleate [624-48-6] is produced in a first step from maleic anhydride and methanol with a strongly acidic ion exchanger as catalyst. The resulting dimethyl maleate is hydrogenated in the gas phase on a Cu-containing catalyst at a pressure of 2 – 8 MPa at 150 – 250 °C and gives a mixture of 1,4-butanediol, tetrahydrofuran, butyrolactone, and a small amount of the intermediate dimethyl succinate [106-65-0].
Butyrolactone and dimethyl succinate can be recovered as an azeotrope and recycled to the hydrogenation stage to obtain complete conversion to 1,4-butanediol and tetrahydrofuran. Alternatively the azeotrope can be refined by distillation to recover pure butyrolactone. The amount of butyrolactone depends on the pressure and temperature in the hydrogenation step, which influence the equilibrium between 1,4-butanediol and butyrolactone. Under the conditions described above it may vary from 5 to 50 %.
The new process has been licensed by KPT several times. The first commercial plants using this process are expected to come on stream in 2000.
A proprietary process practised by Eurodiol, a Belgian company of the SISAS group also starts from dimethyl maleate, which is hydrogenated in the gas phase at 1 – 2 MPa to give a mixture of butyrolactone and tetrahydrofuran in variable proportions. Butyrolactone and tetrahydrofuran are recovered as pure products by distillation, while the byproduct azeotrope butyrolactone/dimethyl succinate can be recycled for full conversion to butyrolactone and tetrahydrofuran or hydrogenated in a subsequent hydrogenation step in the liquid phase to give 1,4-butanediol and additional tetrahydrofuran.
Other Processes. Processes via tetrahydrofuran [11], dihydrofuran [12], acetylene [13], [14], butynediol [15], olefins [16][17][18], butadiene [8], or by carbonylation [19][20][21] are not industrially important.
Producers.
Butyrolactone is manufactured by BASF (Ludwigshafen, Germany and Geismar, USA), ISP (Calvert City and Texas City, USA), Lyondell (Channelview, USA), MCC (Mizushima, Japan) and Eurodiol (Feluy, Belgium).
[7] S. Oka, Bull. Chem. Soc. Jpn. 35 (1962) 986 – 989.
[8] Mitsubishi Petrochemical, DE-OS 1593073, 1966; DE-OS 1901870, 1969 (T. Asano, J. Kanetaka).
[9] J. Kanetaka, T. Asano, S. Masumune, Ind. Eng. Chem. 62 (1970) 24 – 32. T. Yoshimura, Chem. Eng. N.Y. 76 (11. Aug. 1969) 70 – 72; Chem. Week 104 (1969) 63 – 72. S. Minoda, M. Miyajima, Hydrocarbon Process. 49 (1970) no. 11, 176 – 178.
[10] M. W. M. Tuck, M. A. Wood, C. Rathmell, P. H. E. Eastland: "Butane to Butanediol: The emergence of a new Process Route," AIChE 1994 Spring International Meeting.
[11] Quaker Oats, US 3074964, 1961 (A. P. Dunlop, E. Sherman).H. Hara, JP-Kokai 7887347, 1978.
[12] BASF, DE 4 339 269, 1993 (R. Pinkos, R. Fischer).
[13] BASF, WO 9 707 111, 1995 (M. Heider et al.).
[14] BASF, DE 19 530 549, 1995 (M. Heider, T. Ruehl, J. Henkelmann, S. Stutz).
[15] Y. Shvo, Y. Blum, J. Organomet. Chem. 238 (1982) C 79 – C 81.
[16] Toa Nenryo Kogyo K.K., JP-Kokai 75 154 237, 1975 (Y. Okumura, Y. Nagashima).
[17] Nat. Dist. and Chem. Corp., US 4 247 467, 1978 (J. H. Murib).
[18] Standard Oil, US 4 238 357, 1980 (Th. Haase, F. A. Pesa).
[19] Texaco, US 3 061 614, 1958 (W. M. Sweeney, J. A. Patterson).
[20] The British Petroleum Company, EP 176 370, 1984 (H. Alper, D. J. H. Smith).
[21] ARCO Chem. Technology LP, US 5 401 857, 1994 (D. Armstead, R. A. Grey).
Taken from Ullman's Encyclopedia of industrial chemistry