The present invention relates to a process for catalytically hydrogenating a hydrogenatable precursor in contact with a hydrogen-containing gas and a hydrogenation catalyst comprising one or more active hydrogenation catalyst components on a support comprising titanium dioxide in the rutile form to produce 1,4-butanediol (BDO) and, optionally, gamma-butyrolactone (GBL) and/or tetrahydrofuran (THF).
This invention also relates to a process for the hydrogenation of maleic acid to 1,4-butanediol and, optionally, gamma-butyrolactone and/or tetrahydrofuran wherein selective reduction of maleic acid to succinic acid, is achieved in the first step of the hydrogenation process by using a catalyst supported on titanium dioxide in the rutile form and selective reduction of the succinic acid is achieved in the second step of the hydrogenation process by using a hydrogenation catalyst comprising one or more active hydrogenation catalyst components supported on titanium dioxide in the rutile form, a hydrogenation catalyst supported on carbon, or mixtures thereof.
This invention further relates to a process for the production of succinic acid or succinic anhydride by the hydrogenation of maleic acid to produce succinic acid using a hydrogenation catalyst comprising one or more active hydrogenation catalyst components supported on titanium dioxide in the rutile form, and then, optionally, dehydrating the succinic acid to convert the succinic acid to succinic anhydride.
In one embodiment, at least about one weight percent, preferably at least about 80 weight percent, more preferably at least about 90 weight percent, more preferably at least about 95 weight percent and more preferably 100 weight percent of the titanium dioxide catalyst support is in the rutile crystalline phase.
1,4-Butanediol (BDO) is a commercial commodity with a plurality of uses. For example, 1,4-butanediol is used in the production of polybutylene terepthalate and reaction-injected molded (RIM) urethanes. 1,4-butanediol is also used in polytetramethylene ether glycol (PTMEG), which is employed as a raw material for spandex. Tetrahydrofuran is a useful solvent for natural and synthetic resins and is a valuable intermediate in the manufacture of a number of chemicals and plastics. Gamma-butyrolactone is an intermediate for the synthesis of butyric acid compounds, polyvinylpyrrolidone and methionine. Gamma-butyrolactone is a useful solvent for acrylate and styrene polymers and also a useful ingredient of paint removers and textile assistants. 1,4-butanediol (a.k.a. 1,4-butylene glycol) is useful as a solvent, a humectant, an intermediate for plasticizers and pharmaceuticals, a cross-linking agent for polyurethane elastomers, a precursor in the manufacture of tetrahydrofuran, and is used to make terephthalate plastics.
It is well known that 1,4-butanediol may be obtained by the catalytic hydrogenation of maleic acid, maleic anhydride and similar hydrogenatable compounds. In such processes, aqueous maleic acid is fed with hydrogen to a reactor containing a fixed bed catalyst. The reaction products containing 1,4-butanediol, tetrahydrofuran and gamma-butyrolactone are then recovered and purified by conventional means.
British Patent No. 1,534,232 teaches the hydrogenation of carboxylic acids, lactones or anhydrides using a hydrogenation catalyst consisting of palladium and rhenium on a carbon support. U.S. Pat. Nos. 4,550,185 and 4,609,636 teach a process of making tetrahydrofuran and 1,4-butanediol by hydrogenating maleic acid, maleic anhydride or another hydrogenatable precursor in the presence of a catalyst comprising palladium and rhenium on a carbon support wherein the palladium and rhenium were present in the form of crystallites having an average palladium crystallite size of about 10 to 25 nm and an average rhenium crystallite size of less than 2.5 nm. The preparation of this catalyst is characterized by the deposition and reduction of the palladium species on the carbon support followed by the deposition and reduction of the rhenium species on the palladium impregnated carbon support.
U.S. Pat. No. 4,985,572 teaches a process for the catalytic hydrogenation of a carboxylic acid or an anhydride thereof to the corresponding alcohol and/or carboxylic acid ester using a catalyst comprising rhenium, palladium and silver on a carbon support. The preparation of this catalyst is characterized by the simultaneous deposition of palladium and silver on the carbon support followed by a high temperature (600° C.) heat treatment. Rhenium was then deposited on the palladium/silver impregnated carbon support. The resulting catalyst was then reduced.
U.S. Pat. No. 5,473,086 discloses a process for the production of tetrahydrofuran and 1,4-butanediol comprising catalytically hydrogenating a hydrogenatable precursor in contact with a hydrogen-containing gas and a hydrogenation catalyst comprising palladium, silver and rhenium on a carbon support to produce a product comprising a major portion of 1,4-butanediol wherein the hydrogenation catalyst is prepared by the steps of (i) impregnating the carbon support with a source of palladium, silver and rhenium in one or more impregnation steps comprising contacting the carbon support with a source of palladium, silver and rhenium, said palladium, silver and rhenium being in at least one solution; (ii) drying the impregnated carbon support to remove solvent after each impregnation step; and (iii) heating the impregnated carbon support at a temperature of about 100° C. to about 350° C. under reducing conditions.
U.S. Pat. No. 5,698,749 discloses a process for the production of 1,4-butanediol comprising catalytically hydrogenating a hydrogenatable precursor in contact with a hydrogen-containing gas and a hydrogenation catalyst comprising at least one noble metal of Group VIII of the Periodic Table and at least one of rhenium, tungsten and molybdenum deposited on a carbon support, wherein the carbon support has been contacted with an oxidizing agent selected from the group consisting of nitric acid, hydrogen peroxide, sodium hypochlorite, ammonium persulfate and perchloric acid prior to the deposition of the metals.
U.S. Pat. No. 5,969,164 discloses a catalyst for the hydrogenation of maleic acid, maleic anhydride or other hydrogenatable precursor to 1,4-butanediol and tetrahydrofuran has been discovered. This hydrogenation catalyst comprises palladium, silver, rhenium and at least one of iron, aluminum, cobalt and mixtures thereof, all on a carbon support.
U.S. Pat. No. 6,486,367 discloses a process for the production of 1,4-butanediol comprising catalytically hydrogenating a hydrogenatable precursor in contact with a hydrogen-containing gas and a hydrogenation catalyst comprising at least one noble metal of Group VIII of the Periodic Table, selected from the group consisting of palladium, ruthenium, rhodium, osmium, iridium and platinum wherein iron is added to the hydrogenatable precursor. The catalyst is supported on carbon.
Carbon has generally been used as the support material for the hydrogenation metal in the catalyst employed in prior hydrogenation processes for preparing 1,4-butanediol. A common disadvantage of the use of a carbon support is that carbon fines are often generated during commercial operations. The generation of such fines can be minimized but generally cannot be completely avoided. During the hydrogenation process, such particulates can plug the void spaces in the catalyst through which the reactants must flow and thereby cause interruptions in the process.
Carbon supports may flake under the reaction conditions. Flaking or breaking of the carbon support can cause a higher pressure differential (delta P) because the pores or void spaces in the catalyst are blocked so that the hydrogenatable precursor feed cannot pass through effectively. This can lead to crushing of the catalyst.
For this reason, it is highly desirable to use other materials as the support material in the catalyst employed in the maleic acid hydrogenation process. However, because of the highly corrosive conditions under which the aforesaid hydrogenation is performed, it has proven difficult to develop suitable non-carbon catalyst supports for use in the hydrogenation catalyst. Hot aqueous solutions of maleic acid may dissolve or attack and pit some types of supporting materials.
U.S. Pat. No. 4,782,167 discloses a process for producing butyrolactones, butanediols, and mixtures thereof comprising hydrogenating a hydrogenatable precursor in the presence of an aqueous reaction medium and a catalyst comprising palladium or combinations thereof with rhenium and at least one support selected from the oxides of titanium, zirconium, and hafnium. There is no disclosure of the use of titanium dioxide in the rutile crystalline phase as a catalyst support.
Canadian Patent No. 1070711 discloses a process for the production of 1,4-butanediol from maleic anhydride, maleic acid or mixtures thereof in one step in the presence of catalysts comprising simultaneously elements of subgroup VII or compounds thereof, or elements of subgroup VIII or elements thereof, or mixtures of these elements and compounds. The catalyst elements can be manganese, rhenium, ruthenium, rhodium, palladium, osmium, iridium, and platinum; and rhenium, palladium and platinum are used preferably. The catalyst elements can be palladium and rhenium. The catalyst can be on a support, which can be silicon dioxide, titanium dioxide, silicon dioxide-aluminum oxide, carbon, thorium oxide, zirconium oxide, silicon carbide, spinels, and aluminum oxide. The solvent can be water when maleic acid is the starting material. There is no disclosure of the use of titanium dioxide in the rutile crystalline phase as a catalyst support.
U.S. Pat. No. 5,985,789 discloses improved hydrogenation catalysts consisting essentially of reduced or at least partially reduced ruthenium and tin on a refractory oxide support, such as titanium oxide or zirconium oxide which is insoluble in aqueous acid. The catalysts are used for the conversion of hydrogenatable precursors, such as maleic acid, succinic acid, gamma-butyrolactone to 1,4-butanediol and gamma-butyrolactone and their mixtures. There is no disclosure of the use of titanium dioxide in the rutile crystalline phase.
M. Bankmann, R. Brand, B. H. Engler and J. Ohmer, “Forming of High Surface Area TiO2 to Catalyst Supports,” Catalysis Today, Vol. 14, pages 225-242 (1992), contains an extensive discussion of the use of titanium dioxide having a high surface area as a catalyst support. The article (which was previously presented in a substantially identical form by R. Brand at the Fall, 1991 American Chemical Society meeting) indicates that the titanium dioxide must have a high surface area in order to be a suitable catalyst support and discusses only titanium dioxide having surface areas of 50 and 100 square meters per gram. The article discusses the extrusion process for manufacturing titanium dioxide having the requisite high surface area and the effect of the raw materials, additives and process parameters employed in the extrusion process on catalytically important characteristics of the resulting titanium dioxide. As disclosed, the extrusion process involves the steps of: (1) mixing and kneading the raw materials, (2) extruding, (3) drying, and (4) calcining, each of which influences the quality of the resulting support. Correlations between the concentration of water, plasticizers and binders and the type of titanium dioxide raw material employed in the mixing and kneading step and the crushing strength, attrition resistance, pore diameter and pore volume of the resulting catalyst support, and correlations between the calcination temperature and the surface area, pore volume, mean pore diameter and pore size distribution and the degree of transformation from the anatase crystalline phase to the rutile crystalline phase in the resulting catalyst support, are discussed in the article. More particularly, the use of catalysts containing palladium, platinum or rhodium components supported on titanium dioxide for selective hydrogenation is disclosed. On pages 240 to 241, the use of such catalysts to hydrogenate a para-substituted benzaldehyde to the corresponding para-substituted benzyl alcohol or para-substituted toluene is disclosed. The table on page 241 indicates that the para-substituent can be a carboxylic acid group, a methyl group or a halogen. The article discloses that the results of the hydrogenation of para-substituted benzaldehyde were substantially different depending upon whether the catalyst contained palladium, platinum or rhodium on the titanium dioxide support. The article indicates that the titanium dioxide must have a high surface area in order to be a suitable catalyst support and discusses only titanium dioxide having surface area of 50 and 100 square meters per gram. In addition, the article discloses that depending on the reaction temperature employed, the reduction of a para-substituted benzaldehyde affords either of several products with high selectivity and in high yield. Except for the catalysis, the reaction temperature and the hydrogen pressure employed, the article does not disclose the conditions under which the hydrogenation was performed.
In commonly assigned U.S. Pat. No. 5,362,908, to Schroeder et al., a method employing a titanium dioxide-supported purification catalyst is disclosed for purification-by-hydrogenation of a crude terephthalic acid, crude isophthalic acid or a crude naphthalene dicarboxylic acid produced by the liquid-phase oxidation with an oxygen-containing gas in a solvent at an elevated temperature and pressure and in the presence of an oxidation catalyst comprising a heavy metal component. The purification-by-hydrogenation process according to U.S. Pat. No. 5,362,908 comprises passing an at least partially aqueous solution of crude aromatic dicarboxylic acid at a pressure sufficient to maintain the solution substantially in the liquid phase through a particulate catalyst bed in the presence of hydrogen. Particulate catalyst for this purification-by-hydrogenation process is a noble metal of Group VIII of the Periodic Table of Elements on a titanium dioxide support which does not disintegrate in less than one month under conditions employed in the hydrogenation. Preferably, at least one weight percent of the titanium dioxide support is in the rutile crystalline phase, and at least about 90 weight percent of the titanium support is, more preferably, in the rutile crystalline phase. However, even after hydrogenation, the terephthalic acid product contains color bodies.
Commonly assigned U.S. Pat. No. 5,616,792 discloses processes using a titanium dioxide-supported purification catalyst for purification of relatively impure dicarboxylic aromatic acid produced by liquid-phase oxidation of a suitable benzene or naphthalene having two oxidizable ring substituents, and/or by recovery from polyester resin comprising repeating units of the dicarboxylic aromatic acid residue and repeating units of dihydric alcohol residue. Purification comprises passing an aqueous solution of dicarboxylic aromatic acid with small amounts of organic impurities consisting of oxygen-containing aromatic co-products of oxidation and/or other organic components, through a particulate bed of purification catalyst comprising a noble metal on a titanium dioxide support under conditions suitable for decarbonylation of organic impurities. Generally, at least one weight percent of the titanium dioxide support is in the ruffle crystalline phase. Optionally, effluent aqueous solution from the bed containing noble metal on the titanium dioxide support is passed through a subsequent particulate bed of another purification catalyst in the presence of a molecular hydrogen-containing gas. Hydrogenation of the aqueous solution subsequent to decarbonylation further reduces organic impurities in dicarboxylic aromatic acid recovered by crystallization and separation from the aqueous solution.
Commonly assigned U.S. Pat. No. 5,756,833 discloses processes using a titanium dioxide-supported purification catalyst for purification of relatively impure dicarboxylic aromatic acid produced by liquid-phase oxidation of a suitable benzene or naphthalene having two oxidizable ring substituents, and/or by recovery from polyester resin comprising repeating units of the dicarboxylic aromatic acid residue and repeating units of dihydric alcohol residue. Purification comprises passing an aqueous solution of dicarboxylic aromatic acid with small amounts of organic impurities consisting of oxygen-containing aromatic co-products of oxidation and/or other organic components, through a particulate bed of purification catalyst comprising a noble metal on a titanium dioxide support under conditions suitable for decarbonylation of organic impurities. Generally, at least one weight percent of the titanium dioxide support is in the rutile crystalline phase. Optionally, effluent aqueous solution from the bed containing noble metal on the titanium dioxide support is passed through a subsequent particulate bed of another purification catalyst in the presence of a molecular hydrogen-containing gas. Hydrogenation of the aqueous solution subsequent to decarbonylation further reduces organic impurities in dicarboxylic aromatic acid recovered by crystallization and separation from the aqueous solution.
Titanium dioxide which is primarily in the anatase crystalline phase also has disadvantages as a catalyst support. The anatase TiO2 has a low crush strength and is also subject to disintegrating and producing particles which can clog the catalyst pores and reduce the efficiency of the reaction.
There are many areas where improvement is needed in catalysts previously used to produce BDO, GBL, and THF. Some of these are: more uniform particle length distribution, minimization of fines and chips to reduce delta P, harder particles for retarding the delta P increase due to degradation, longer life at full rate of production. It may be possible to increase production if one can reduce the bed delta P.
An object of this invention is a process and a catalyst which can maximize 1,4-butanediol production and minimize gamma-butyrolactone production. Such a catalyst would be more economical because more of the more desired BDO product would be produced and because recycling GBL increases the overall process costs.
A catalyst which does not require the use of sodium, iron, and silver, in which the amount of palladium and rhenium can be reduced, and in which carbon is replaced with a much harder, more uniform support would also be more economical and would be desirable. The present invention provides such a catalyst by using a hydrogenation catalyst comprising one or more active hydrogenation catalyst components on a catalyst support comprising titanium dioxide in the rutile crystalline phase.
The catalyst of the present invention provides the above desired features. The present invention uses a catalyst comprising a hydrogenation catalyst comprising one or more active hydrogenation catalyst components on a support comprising titanium dioxide in the rutile crystalline phase to overcome disadvantages, such as flaking, high delta P, and low crush strength, found with other catalyst supports. The catalyst of the present invention also has the advantage that less nitric acid is needed for catalyst preparation which makes use of the catalyst less adverse to the environment and more desirable where the impact on the environment is an important factor.
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