Title of Invention

AN IMPROVED PROCESS FOR THE PREPARATION OF 1,4-BUTANEDIOL

Abstract

The present reports an improved process for the preparation of 1, 4-butanediol which comprises reducing a solution of 2-butene-l,4-diol in a solvent at a temperature ranging between 25 to lOOOc and pressure of hydrogen in the range of 10 to 60 psi, in the presence of catalyst selected from hydroxides of Pd-C, PtO2 , raney nickel catalyst for a period ranging between 1 to 24 hrs., separating the solid catalyst by conventional method, neutralizing the filtrate with acid, removing the solvent, and isolating the product, 1,4-butanediol, by distillation under reduced pressure.

Full Text

This invention relates to an improved process for the preparation of 1,4-butanediol. More particularly it describes a process for 1,4-butanediol by hydrogenation of 2-butene-l,4-diol. Still more particularly, the present invention relates to an improved process for the preparation of 1,4-butanediol from 2-butene-l,4-diol by hydrogenation using Raney nickel catalyst. 1,4-Butanediol is an important intermediate in the manufacture of polyethers, polyols, copolyester ethers, elastomers, thermoplastic polyurethanes, and spandex fibers (M. L. Morgan, Chem. & Industry, 1997, 166]. In a prior art various methods have been described for the preparation of 1,4-butanediol. In one of the method, acetylene is reacted with formaldehyde to get 1,4-butynediol, which on two stage hydrogenation in presence of Pd on alumina resulted in the formation of 1,4-butanediol along with small amount of 4-hydroxybutyraldehyde and 2-butene-l,4-diol {Ger (east) DD 26539, (1989)}. In another method, 1,4-butanediol is prepared by hydrogenation of 2-butene-l,4-diol in presence of catalysts containing metal salts of Fe, Co, Ca, Cr, Ti and Ni impregnated on silicagel, at 10 atm. pressure and 80°C temperature (Japan Kokai 7449910 (1972)}. In yet another method, 1,4-butanediol is obtained in three step process from 1,3-butadiene by acetoxylation, hydrogenation followed by hydrolysis (a) US 3,922, 300 (1975); b) US 4,225,729 (1980)}. In yet another method, 1,4-butanediol is prepared from epoxybutene {US 3,932,468 (1975)}. ARCO has developed a three step process for 1,4-butanediol from propylene oxide, which includes isomerization of propylene oxide to allyl alcohol at 250 - 300°C and about 10 bar pressure, hydroformylation of allyl alcohol to 4-hydroxybutyraldehyde and hydrogenation of 4-hydroxy-butyraldehyde to 1,4-butanediol {(a) US 4,567,305 (1986); b) EP Appl No. 129802 Al (1984); c) US 4,537,997 (1985); d) US 4,465,873 (1984)}. In a similar method allyl ethers on hydroformulation, hydrogenation followed by hydrolysis gave 1,4-butanediol {(a) EP Appl. No. 18163 (1980); b) EP Appl. No. 18164 (1980)}. In a yet another process, 1,4-butanediol is obtained as by product along with tetrahydrofuran, is based on vapor phase hydrogenation of maleic anhydride or succenic anhydride, {(a) EP Appl. No. 147219 Bl (1989); (b) US 4,810,807(1989)}. In a yet another process 1,4-butanediol is produced as a mixture of 1,2- and 1,4-butanediol, by reacting, 1,3-butadiene with tert-butylhydroperoxide in the presence of a cobalt on silica catalyst, followed by-catalytic hydrogenation of di (tert-butylperoxy)butene obtained at 200-1300 psi H2 pressure {S. C. Tang and K. Tex, US 4,384,146 (1983)}. The hydrogenation of 1,4-butynediol and 2-buterie-l,4-diol over various palladium catalysts are carried out to get 1,4-butanediol [Bull. Chem. Soc. Japan, 1958, 31, 343]. In most of the prior art process described hereinbefore involve more steps and are less selective, and moreover lead to the formation of mixture of products from which desired product, 1,4-butanediol, has to be separated. The drawback of some of the prior art are the hydrogenation step is carried out at very high pressure and temperature. The main object of this invention is to provide an improved process for the preparation of 1,4-butanediol with very high selectivity and which do not have the limitations of the prior art processes, described herein above. Another object of this invention is to provide a process for the preparation of 1,4-butanediol, wherein the hydrogenation can be carried out at relatively lower temperature and pressure. Accordingly, the present invention provides an improved process for the preparation of 1, 4-butanediol which comprises reducing a solution of 2-butene-1.4-diol in a solvent at a temperature ranging between 25 to 100°C and pressure of hydrogen in the range of 10 to 60 psi, in the presence of catalyst selected from hydroxides of Pd-C, PtO2 , raney nickel catalyst for a period ranging between 1 to 24 hrs., separating the solid catalyst by conventional method, neutralizing the filtrate with acid, removing the solvent, and isolating the product, 1,4-butanediol, by distillation under reduced pressure. In an embodiment of the present invention, the solvent used may be such as water, methanol, ethanol, propanol, acetonitrile, THF, acetone. In an another embodiment the catalyst used may be such as Pd-C, Pt02 , Raney nickel catalyst. In yet another embodiment the acid used for neutralization may be such as HC1, H2S04, acetic acid, oxalic acid and the like. The process of the present invention is described hereinbelow with reference to the examples, which are illustrative only and should not be construed to limit the scope of the invention in any manner. Example 1 A mixture of 2-butene-l,4-diol (4.81 g), methanol (25 ml), Raney nickel (200 mg) and potassium hydroxide (1.25 g) is taken in a Parr reactor and flushed with hydrogen gas three times. The reactor is pressurized with hydrogen (10 psi) and heated at 60 °C with stirring for 3 hr. The reaction mixture is cooled and filtered to remove the catalyst. The filtrate is neutralized with acetic acid and the solvent is removed by distillation. The residue is distilled under reduced pressure to get 1,4-butanediol as a colorless oil with 100% selectivity and 70% conversion. Example 2 A mixture of 2-butene-l,4-diol (2.00 g), methanol (60 ml), Raney nickel (300 mg) and potassium hydroxide (0.60 g) is taken in a Parr reactor and flushed with hydrogen gas three times. The reactor is pressurized with hydrogen (25 psi) and heated at 60 °C with stirring for 3 hr. The reaction mixture is cooled and filtered to remove the catalyst. The filtrate is neutralized with acetic acid and the solvent is removed by distillation. The residue is distilled under reduced pressure to get 1,4-butanediol as a colorless oil with 95% selectivity and 100% conversion. Example 3 A mixture of 2-butene-l,4-diol (2.00 g), methanol (60 ml), Raney nickel (300 mg) and potassium hydroxide (1.20 g) is taken in a Parr reactor and flushed with hydrogen gas three times. The reactor is pressurized with hydrogen (30 psi) and heated at 60 °C with stirring for 3 hr. The reaction mixture is cooled and filtered to remove the catalyst. The filtrate is neutralized with oxalic acid and the solvent is removed by distillation. The residue is distilled under reduced pressure to get 1,4-butanediol as a colorless oil with 99% selectivity and 70% conversion. Example 4 A mixture of 2-butene-l,4-diol (2.00 g), ethanol (60 ml), Raney nickel (300 mg) and sodium hydroxide (1.20 g) is taken in a Parr reactor and flushed with hydrogen gas three times. The reactor is pressurized with hydrogen (30 psi) and heated at 65 °C with stirring for 3 hr. The reaction mixture is cooled and filtered to remove the catalyst. The filtrate is neutralized with acetic acid and the solvent is removed by distillation. The residue is distilled under reduced pressure to get 1,4-butanediol as a colorless oil with 95% selectivity and 100% conversion. Example 5 A mixture of 2-butene-l,4-diol (2.00 g), methanol (25 ml), Raney nickel (300 mg) and potassium hydroxide (1.20 g) is taken in a Parr reactor and flushed with hydrogen gas three times. The reactor is pressurized with hydrogen (30 psi) and heated at 65 °C with stirring for 2 hr. The reaction mixture is cooled and filtered to remove the catalyst. The filtrate is neutralized with acetic acid and the solvent is removed by distillation. The residue is distilled under reduced pressure to get 1,4-butanediol as a colorless oil with 100% selectivity and 80% conversion. Example 6 A mixture of 2-butene-l,4-diol (2.00 g), ethanol (25 ml), Raney nickel (300 mg) and lithium hydroxide (1.20 g) is taken in a Parr reactor and flushed with hydrogen gas three times. The reactor is pressurized with hydrogen (25 psi) and heated at 70 °C with stirring for 2.5 hr. The reaction mixture is cooled and filtered to remove the catalyst. The filtrate is neutralized with dil. HC1 and the solvent is removed by distillation. The residue is distilled under reduced pressure to get 1,4-butanediol as a colorless oil with 100% selectivity and 90% conversion. Example 7 A mixture of 2-butene-l,4-diol (5.00 g), water (65 ml), Raney nickel (600 mg) and potassium hydroxide (1.25 g) is taken in a Parr reactor and flushed with hydrogen gas three times. The reactor is pressurized with hydrogen (30 psi) and heated at 65 °C with stirring for 5 hr. The reaction mixture is cooled and filtered to remove the catalyst. The filtrate is neutralized with acetic acid and the solvent is removed by distillation. The residue is distilled under reduced pressure to get 1,4-butanediol as a colorless oil with 100% selectivity and 70% conversion. Example 8 A mixture of 2-butene-l,4-diol (2.00 g), THF (60 ml), Raney nickel (300 mg) and cesium hydroxide (1.20 g) is taken in a Parr reactor and flushed with hydrogen gas three times. The reactor is pressurized with hydrogen (30 psi) and heated at 60 °C with stirring for 4 hr. The reaction mixture is cooled and filtered to remove the catalyst. The filtrate is neutralized with dil. H2S04 and the solvent is removed by distillation. The residue is distilled under reduced pressure to get 1,4-butanediol as a colorless oil with 100% selectivity and 90% conversion. Example 9 A mixture of 2-butene-l,4-diol (2.00 g), acetonitrile (60 ml), Raney nickel (300 mg) and sodium hydroxide (1.20 g) is taken in a Parr reactor and flushed with hydrogen gas three times. The reactor is pressurized with hydrogen (30 psi) and heated at 60 °C with stirring for 3 hr. The reaction mixture is cooled and filtered to remove the catalyst. The filtrate is neutralized with acetic acid and the solvent is removed by distillation. The residue is distilled under reduced pressure to get 1,4-butanediol as a colorless oil with 95% selectivity and 80% conversion. Example 10 A mixture of 2-butene-l,4-diol (2.00 g), methanol (60 ml), Raney nickel (300 mg) and sodium hydroxide (1.20 g) is taken in a Parr reactor and flushed with hydrogen gas three times. The reactor is pressurized with hydrogen (40 psi) and heated at 25 °C with stirring for 24 hr. The reaction mixture is cooled and filtered to remove the catalyst. The filtrate is neutralized with acetic acid and the solvent is removed by distillation. The residue is distilled under reduced pressure to get 1,4-butanediol as a colorless oil with 100% selectivity and 30% conversion. Example 11 A mixture of 2-butene-l,4-diol (2.00 g), methanol (60 ml), Raney nickel (300 mg) and sodium hydroxide (1.20 g) is taken in a Parr reactor and flushed with hydrogen gas three times. The reactor is pressurized with hydrogen (40 psi) and heated at 25 °C with stirring for 24 hr. The reaction mixture is cooled and filtered to remove the catalyst. The filtrate is neutralized with acetic acid and the solvent is removed by distillation. The residue is distilled under reduced pressure to get 1,4-butanediol as a colorless oil with 100% selectivity and 30% conversion. Example 12 A mixture of 2-butene-l,4-diol (2.00 g), ethanol (60 ml), Raney nickel (300 mg) and potassium hydroxide (1.20 g) is taken in a Parr reactor and flushed with hydrogen gas three times. The reactor is pressurized with hydrogen (25 psi) and heated at 100 °C with stirring for 2 hr. The reaction mixture is cooled and filtered to remove the catalyst. The filtrate is neutralized with acetic acid and the solvent is removed by distillation. The residue is distilled under reduced pressure to get 1,4-butanediol as a colorless oil with 90% selectivity and 100% conversion. We Claim: 1. An improved process for the preparation of 1, 4-butanediol which comprises reducing a solution of 2-butene-l,4-diol in a solvent at a temperature ranging between 25 to 100°C and pressure of hydrogen in the range of 10 to 60 psi, in the presence of catalyst selected from hydroxides of Pd-C, PtO2 , Raney nickel catalyst for a period ranging between 1 to 24 hrs., separating the solid catalyst by conventional method, neutralizing the filtrate with acid, removing the solvent, and isolating the product, 1, 4-butanediol, by distillation under reduced pressure. 2. An improved process as claimed in claim 1, wherein the solvent used is such as water, methanol, ethanol, propanol, acetonitrile, tetrahydrofuran,acetone. 3. An improved process as claimed in claim 1-2, wherein the catalyst used is such as hydroxides of Pd-C, PtO2, Raney nickel catalyst 4. An improved process as claimed in claims 1-3, wherein the reduction is carried out at 25 to 100°C preferably at 60-70°C. 5. An improved process as claimed in claims 1-4, wherein the acid used for neutralization such as HC1, HjSCM, acetic acid, oxalic acid. 6. An improved process for the preparation of 1, 4-butanediol as substantially described herein with reference to the examples.

Documents:

1117-del-1998-abstract.pdf

1117-del-1998-claims.pdf

1117-del-1998-correspondence-others.pdf

1117-del-1998-correspondence-po.pdf

1117-del-1998-description (complete).pdf

1117-del-1998-form-1.pdf

1117-del-1998-form-19.pdf

1117-del-1998-form-2.pdf