USOO868O350B2

(12) United States Patent (10) Patent No.: US 8,680,350 B2 Hatscher et al. (45) Date of Patent: Mar. 25, 2014

(54) PROCESS FOR HYDROGENATING 6,706,885 B2 3/2004 Yasuda et al. UNSATURATED HYDROCARBONS IN THE 6,723,295 B1 4/2004 Baier et al. 6,987,152 B1* 1/2006 Eisinger et al...... 526/77 PRESENCE OF CATALYSTS CONTAINING 2003.0036669 A1 2/2003 Ryu et al. AND 2004/0176653 A1 9/2004 Vorberg et al. 2005/0241478 A1 11/2005 Junicke et al. (75) Inventors: Stephan Hatscher, Syke (DE); Michael 2007/0117714 A1 5/2007 Geyer et al. Hesse, Worms (DE) FOREIGN PATENT DOCUMENTS

(73) Assignee: BASFSE, Ludwigshafen (DE) BE T48742 10, 1970 DE 1929977 12/1969 (*) Notice: Subject to any disclaimer, the term of this DE 2012430 10, 1971 patent is extended or adjusted under 35 DE 19848595 A1 4/2000 EP O394.842 A1 10, 1990 U.S.C. 154(b) by 752 days. EP 0434062 A1 6, 1991 EP O646410 A1 4f1995 (21) Appl. No.: 12/374,191 EP 1331033 A8 T 2004 WO WO-95,23644 A1 9, 1995 WO WO-96, 14280 A1 5, 1996 (22) PCT Filed: Jul. 5, 2007 WO WO-02/0681 19 A1 9, 2002 WO WO-02/094435 A1 11, 2002 (86). PCT No.: PCT/EP2007/056858 WO WO-2004/004901 A1 1, 2004 WO WO-2004/022223 A2 3, 2004 S371 (c)(1), WO WO-2004/026800 A1 4/2004 (2), (4) Date: Jan. 16, 2009 (87) PCT Pub. No.: WO2008/009568 OTHER PUBLICATIONS PCT Pub. Date: Jan. 24, 2008 Blanco, J., “Catalizadores en la industria: catalizadores heterogeneos. III. Su aplicacion en procesos de hidrogenacion de (65) Prior Publication Data hidrocarburos,” Quimica E Industria, 1974, vol. 20, No. 9, pp. 604 US 2009/0312588 A1 Dec. 17, 2009 606. Carr, N.L., et al., “Remove arsine to protect catalyst.” Hydrocarbon (30) Foreign Application Priority Data Processing, May 1985, pp. 100-102. Derrien, M.L., “Selective hydrogenation applied to the refining of Jul. 17, 2006 (EP) ...... O6117306 petrochemical raw materials produced by Steam cracking.” Stud. Suf. Sci. Catal., 1986, vol. 27, pp. 613-666. (51) Int. Cl. Allmann, H.-M., et al., “Selective hydrogenations and purifications C07C 7/167 (2006.01) in the steamcracker downstream treatment.’ DGMK-Conference: (52) U.S. Cl. Selective Hydrogenation and Dehydrogenation, Nov. 1993, pp. 1-29. USPC ...... 585/262:585/258; 585/259; 502/340; Allmann, H.-M., et al., “Selective hydrogenations and purifications 502/341; 502/345; 502/346 in the steamcracker downstream treatment.’ DGMK-Conference: (58) Field of Classification Search Selective Hydrogenation and Dehydrogenation, Nov. 1993, pp. USPC ...... 585/275,250, 258, 259,262: 502/300, 49-57. 502/.340,341, 343,346, 345 See application file for complete search history. * cited by examiner (56) References Cited Primary Examiner — In Suk Bullock U.S. PATENT DOCUMENTS Assistant Examiner — Bradley Etherton (74) Attorney, Agent, or Firm — Novak Druce Connolly 2,426,604. A * 9, 1947 Frevel ...... 585,262 3,549,719 A * 12/1970 Duyverman et al...... 423,219 Bove + Quigg LLP 3,637,529 A 1/1972 Van Becket al. 3,677,970 A 7, 1972 Mertzweiller et al. 3,701,739 A 10, 1972 Bovarnicket al. (57) ABSTRACT 3,754,050 A * 8/1973 Duyverman et al...... 95/144 3,912,789 A * 10/1975 Frevel et al...... 585,259 Unsaturated hydrocarbons are hydrogenated over catalysts 4.323,482 A 4, 1982 Stiles et al. which comprise copper and Zinc and whose active composi 4,552,861 A 1 1/1985 Courty et al. 4,593,148 A 6, 1986 Johnson et al. tion, in unreduced form, consists essentially of from 10 to 4,705.906 A * 1 1/1987 Brophy et al...... 585,262 95% by weight of copper , calculated as copper(II) 4,780,481 A 10/1988 Courty et al. oxide (CuO), from 5 to 90% by weight of (ZnO), 4,835,132 A 5, 1989 Sambrook optionally from 0.1 to 50% by weight of dioxide 4,871,710 A 10/1989 Denny et al. (ZrO) and optionally from 0.1% by weight to 50% by weight 5,037,793 A 8, 1991 Toussaint et al. of Al-O, the proportions by weight adding up to 100% by 5,453,412 A * 9/1995 Deckers et al...... 502/.342 weight.

5.990,040 A * 1 1/1999 Hu et al...... 502/.342 6,204,416 B1* 3/2001 Liedloff ...... 568.361 6,238,640 B1 5/2001 Eguchi et al. 6,689,713 B1* 2/2004 Zhao et al...... 502,345 14 Claims, No Drawings US 8,680,350 B2 1. 2 PROCESS FOR HYDROGENATING che Gesellschaft für Erdöl, Erdgas und Kohle e.V., Hamburg, UNSATURATED HYDROCARBONS IN THE p. 49-57 (ISSN 0938-068X, ISBN 3-928164-61-9). PRESENCE OF CATALYSTS CONTAINING In general, unsaturated compounds with triple bonds COPPER AND ZINC (alkynes) and/or diunsaturated compounds (dienes) and/or other di- or polyunsaturated compounds (polyenes, allenes, CROSS-REFERENCE TO RELATED alkylenes) and/or aromatic compounds having one or more APPLICATIONS unsaturated Substituents (phenylalkenes and phenylalkynes) should therefore usually be removed from hydrocarbon This application is a national stage application (under 35 streams in order to obtain the desired products, such as eth 10 ylene, propylene, 1-butene, isobutene, 1,3-butadiene, aro U.S.C. S371) of PCT/EP2007/056858, filed Jul. 5, 2007, matics or carburetor fuel, in the required quality. Not every which claims benefit of European application 06117306.8. unsaturated compound is, however, an undesired component filed Jul. 17, 2006. which should be removed from the hydrocarbon stream in BACKGROUND OF THE INVENTION question. For example, 1,3-butadiene, as already indicated 15 above, is an undesired secondary component or the desired product of value depending on the case. The present invention relates to a process for hydrogenat The removal of undesired unsaturated compounds from ing unsaturated hydrocarbons using catalysts comprising hydrocarbon streams comprising them is frequently done by copper and zinc. In particular, the invention relates to a pro selectively hydrogenating some or all of the undesired unsat cess for hydrogenating alkynes using catalysts comprising urated compounds in the corresponding hydrocarbon Stream, copper and Zinc and especially to a process for hydrogenating preferably by selective hydrogenation to undisruptive, more alkynes in the presence of alkenes. highly saturated compounds, and, in a particularly preferred In refineries and petrochemical plants, hydrocarbon manner, to components of the hydrocarbon streams which streams are obtained, stored and processed on a grand scale. constitute the products of value. For example, acetylene is In these hydrocarbon streams, unsaturated compounds, 25 hydrogenated to ethylene in C2 streams, propyne and allene whose presence is known to to problems especially in to propylene in C3 streams, butyne to butenes, vinylacetylene processing and/or storage, or which are not the desired prod to 1,3-butadiene and/or 1,3-butadiene to butenes in C4 uct of value, are frequently present, and are therefore undes streams, and phenylacetylene and styrene to ethylbenzene, ired components of the corresponding hydrocarbon streams. cyclopentadiene to cyclopentene and pentadiene to pentene General overviews of Such problems in steamcrackers and 30 in C5-- streams. typical solutions were given, for example, by H.-M. Allmann, Typically, such compounds should be removed down to Ch. Herion and P. Polanek in their presentation “Selective residual contents of a few ppm by weight. ("Over-)hydroge Hydrogenations and Purifications in the Steamcracker Down nation to compounds which are more highly saturated than Stream Treatment at the DGMK Conference “Selective the desired product of value and/or parallel hydrogenation of Hydrogenation and Dehydrogenation' on Nov. 11 and 12, 35 a product of value comprising one or more multiple bonds to 1993, in Kassel, Germany, whose manuscript was also pub the corresponding more highly Saturated or completely satu lished in Conference Report 93.05 of the DGMK Deutsche rated compound should, however, be avoided as far as pos Wissenschaftliche Gesellschaft für Erdöl, Erdgas und Kohle sible owing to the associated loss of value. The selectivity of e.V., Hamburg, p. 1-30 (ISSN 0938-068X, ISBN 3-928164 the hydrogenation of the undesired unsaturated compounds 61-9), and M. L. Derrien in: L. Cerveny (ed.), Stud. Surf. Sci. 40 therefore has to be as high as possible. In addition, a suffi Catal, Vol. 27, p. 613-666, Elsevier, Amsterdam 1986. ciently high activity of the catalyst and a long lifetime are Typically, the acetylene secondary component is undesired generally desired. At the same time, the catalyst should as far in C2 streams from Steamcrackers, the propyne and allene as possible also not bring about any undesired side reactions; secondary components are undesired in C3 streams, and the for example, catalysis of the isomerization of 1-butene to 1- and 2-butyne, 1.2-butadiene and vinylacetylene secondary 45 2-butenes, with the exception of special cases, should as far as components are undesired in C4 streams when 1,3-butadiene possible be avoided. Processes for selectively hydrogenating is to be obtained as the product of value and processed further, unsaturated compounds in hydrocarbon streams comprising and also said secondary components and 1,3-butadiene itself them are known both in the form of liquid-phase hydrogena in the cases in which 1-butene, 2-butene (in the cis- and/or the tion or mixed gas/liquid phase hydrogenation, in trickle or trans form) or isobutene are the desired products. In the pro 50 liquid-phase mode, and also in the form of pure gas phase cessing of C5+ streams (“C5+”: hydrocarbons having at least hydrogenation, various process technology measures for 5 atoms, pyrolysis gasoline'), di- and polyenes Such improving the selectivity having been published. as pentadiene and cyclopentadiene, alkynes and/or aromatics Typically, Supported noble metal catalysts in which a noble with unsaturated Substituents such as phenylacetylene and metal is deposited on a catalyst Support are used. Frequently, styrene, are undesired when obtaining and processing aro 55 is used as the noble metal; the Support is generally matics or carburetor fuel. a porous inorganic oxide, for example silica, aluminosilicate, In hydrocarbon streams which stem from an FCC cracker dioxide, Zirconium dioxide, Zinc aluminate, Zinc or a reformer instead of a steamcracker, analogous problems titanate and/or mixtures of Such supports, but aluminum occur. A general overview of Such problems, especially in oxide or dioxide are usually used. In addition, promot C4- and C5+ streams from FCC crackers is given, for 60 ers or other additives may be present. One disadvantage of example, by J. P. Boitiaux, C. J. Cameron, J. Cosyns, F. noble metal catalysts (“noble metals” in this field of catalysis Eschard and P. Sarrazin in their presentation “Selective refer to , gold, , , platinum and palla Hydrogenation Catalysts and Processes: Bench to Industrial dium) is their relatively high proneness to contaminations, Scale” at the DGMK Conference “Selective Hydrogenation known as “catalyst poisons'. Such as , , , and Dehydrogenation' on Nov. 11 and 12, 1993, in Kassel, 65 and the like. A further disadvantage is the Germany, whose manuscript has also been published in Con high cost of the noble metals. Although they can generally be ference Report 93.05 of the DGMK Deutsche Wissenschaftli recovered from the catalysts, a considerable amount of capital US 8,680,350 B2 3 4 is tied up during their operation. Often, copper-comprising Al2O catalysts. These are used, for example, for the hydro catalysts are therefore also used for hydrogenation, which are genation of acetone to isopropanol at 200° C. BE 748 7423. A considerably more resistant toward catalyst poisons and con describes the preparation of catalysts having a series of dif siderably less expensive. ferent active compositions on porous Supports by precipitat Copper-comprising catalysts, especially also copper- and ing onto the Support with heating, and the use of Such cata Zinc-comprising catalysts, are known. They are used pre lysts for the hydrogenation of amides at least 50° C. DE-A 20 dominantly as catalysts, absorbents or adsorbents for the 12 430 discloses conversion catalysts composed of 30-55% removal of carbon monoxide from gas streams. WO by weight of CuO, 25-45% by weight of MgO, 2-30% by 02/094435A1 teaches a process for oxidatively removing CO weight of Al-O, and 0-30% by weight of CrO or ZnO.U.S. from ethylene attemperatures in the range from 70 to 110°C. 10 Pat. No. 5.990,040 describes conversion catalysts composed over catalysts comprising copper and zinc. U.S. Pat. No. of 30-70% by weight of CuO, 20-90% by weight of ZnO, 6,238,640 B1 describes a process for removing carbon mon 0.1-20% by weight of an oxide of an element from group IVB. oxide from gas streams comprising by reaction preferably Ti or Zr, 5-50% by weight of Al-O, and 50-1000 with Steam and to give and hydrogen ppm of an oxide of an element from group IA, which may, in the presence of a catalyst which comprises copper oxide 15 though, also be used for methanol synthesis, for purification and aluminum oxide and at least one metal oxide from the and for hydrogenation. U.S. Pat. No. 6,706,885 B2 teaches a group formed from Zinc oxide, oxide and magne process for preparing 2,5-di(3'-aminoprop-1-ynyl)pyridines sium oxide. DE-A 1929 977 teaches catalysts comprising by Sonogashira coupling of 2,5-dihalopyridines with pro from 20 to 60 parts of CuO to 100 parts of ZnO and their use tected 3-aminopropynes over copper, Zinc or Zirconium cata for removing CO from ethylene and propylene streams at a lysts. temperature in the range from 50 to 200° C., WO 2004/ As already mentioned, the use of copper-comprising cata 022223 A2 teaches an adsorption composition comprising lysts for hydrogenations is also known. WO 96/014280 A1 copper, Zinc, Zirconium and optionally aluminum, and its use teaches catalysts which comprise Cu, Zn and at least one for removing CO from streams in the completely reduced compound of Al, Zr, Mg, of a rare earth metal and/or mixtures State. 25 thereof, and their use for hydrogenating carboxylic esters. EP Catalysts comprising copper and Zinc are also known for 434 062 A1 likewise teaches a process for hydrogenating uses other than for the removal of CO from streams, U.S. Pat. carboxylic esters over a catalyst comprising Cu, Al and a No. 4,593,148 and U.S. Pat. No. 4,871,710 disclose processes metal selected from the group formed from Mg., Zn,Ti, Zr, Sn, for desulfurizing and dearsenating with Cu/Zn catalysts. WO Ni, Co and mixtures thereof. EP394 842 A1 teaches catalysts 95/023644 A1 teaches a copper catalyst for the hydrogenation 30 comprising 20-75% by weight of NiO, 10-75% by weight of of carbon , for example to methanol, or for the so ZrO2 and 5-50% by weight of CuO for the hydrogenation of called shift reaction of carbon monoxide with water to give aliphatic unsaturated compounds such as butynediol attem carbon dioxide and hydrogen, which, as well as dispersed peratures in the range from 40°C. to 200° C. and pressures of copper, also comprises stabilizers such as , from 30 to 320 bar. EP 646 410 A1 discloses a process for aluminum oxide, chromium oxide, oxide and/or 35 obtaining alcohols by hydrogenation over a catalyst which Zinc oxide, and optionally also a Support such as aluminum comprises copper and Zinc oxide and a further oxide as the oxide, Zirconium dioxide, and/or silicon active composition on a Support coated with titanium oxide. dioxide. DE 19848 595 A1 discloses a catalyst for nitrous The hydrogenation process is performed at a temperature of oxide decomposition of the general formula MAl-O in from 160° C. to 350° C. EP 1331 033A1 discloses a process which M is Cu or a mixture of Cu and Zn and/or Mg, and 40 for preparing spherical Supported metal catalysts by droplet which may comprise further dopants, especially Zr and/or La. izing a mixture of a polysaccharide and at least one metal U.S. Pat. No. 4.552,861 teaches a preparation process for compound into a metal salt solution. A CuO catalyst on SiO, catalysts which comprise Cu, Zn, Al and at least one element Support prepared in this way is used for the hydrogenation of from the groups formed by the rare earths and Zirconium, and acetophenone at 80° C. and 20 bar of pressure. U.S. Pat. No. also their use for methanol synthesis. The methanol catalysts 45 3,677,970 mentions, as well as the sulfur-resistant disclosed in U.S. Pat. No. 4,780,481 comprise Cu, Zn and at catalysts for the hydrogenation of hydrocarbons disclosed least one alkali metal or alkaline earth metal, noble metals there, also a series of other catalysts which also include cop and/or rare earths, where Zn may be replaced partly by Zr. per catalysts. WO 02/0681 19 A1 discloses a process for pre U.S. Pat. No. 4,835,132 describes CO shift catalysts which paring catalysts comprising copper and at least one further are obtained by from a precursor of the formula 50 element selected from the series of other elements including (Cu+Zn)Al,R,(CO)2OH122-nH2O with layer Zinc by size-buildup granulation. These catalysts are used for structure, where R is La, Ce or Zr, X is at least 1 and at most the hydrogenation of functional organic compounds and for 4, y is at least 0.01 and at most 1.5, and n is about 4. dehydrogenation. WO 2004/026800 A1 describes a process U.S. Pat. No. 4.323,482 discloses methanization catalysts for preparing alcohols by hydrogenating aldehydes over Sul which comprise chromium and nickel and consist of an inti 55 furized copper-zinc oxide catalysts at a temperature of from mate mixture of a reducible metal oxide and at least one 240° C. to 280° C. and an (elevated) pressure of from 20 bar irreducible metal oxide, and which are activated by reduction to 400 bar. at a temperature of from 550 to 1000° C. According to this WO 2004/004901 A1 teaches a process for hydrogenating document, this high temperature to fine metals and C4-acetylenes in a liquid hydrocarbon stream over coated highly active catalysts. As an aside, mention is also made of 60 catalysts comprising copper on Zeolitic Support materials at the application of this catalyst preparation process to copper temperatures in the range of from 20 to 80° C. (in the comprising catalysts. U.S. Pat. No. 3,701.739 likewise examples, temperatures of 60° C. are used) and pressures of teaches catalysts composed of a reducible oxide and at least 15 and 50 bar. N. L. Carr, D. L. Stahlfeld and H. G. Robertson, one irreducible oxide, their preparation from an ammoniacal in Hydrocarbon Processing, May 1985, p. 100-102, report Solution of hydroxides or carbonates, and their uses, includ 65 copper-comprising absorption compositions for removing ing for hydrogenation. Mention is made, for instance, of arsenic from olefin streams. The hydrogenation of the olefins catalysts composed of 30% CuO and 70% ZnO or CuO/ZnO/ is in this case a side reaction which can be suppressed by US 8,680,350 B2 5 6 avoiding temperatures above of 250 F. (corresponding to generally at most 90% by weight, preferably at most 80% by 121° C.). J. Blanco, in Quimica e Industria 20 (1974) 604 weight and more preferably at most 70% by weight, based in 606, reports that hydrocarbons are hydrogenated over copper each case on the total amount of the active composition. In catalysts only attemperatures of at least 300° C. and pressures pure form, it further optionally comprises Zirconium dioxide around 300 bar. 5 ZrO2. When this is present, its proportion is generally at least One disadvantage of common hydrogenation catalysts 0.1% by weight, preferably at least 3% by weight and more with copper as the hydrogenation-active metal is accordingly preferably at least 5% by weight, and generally at most 50% that relatively high hydrogenation temperatures are needed. by weight, preferably at most 40% by weight and more pref However, some streams already exhibit decomposition phe erably at most 30% by weight, based in each case on the total nomena at these temperatures, for example, in typical propy- 10 amount of the active composition. It further optionally com lene streams—which always also comprise traces of oxy prises aluminum oxide Al2O. When this is present, its pro gen—oxygenates are formed even from 50° C. Such portion is at least 0.1% by weight, preferably at least 3% by oxygenates can act as catalyst poisons in downstream pro weight and more preferably at least 50% by weight, and cesses, for instance preparation of polypropylene over met generally at most 50% by weight, preferably at most 40% by allocene catalysts, and are therefore extremely undesirable. 15 weight and more preferably at most 30% by weight, based in The requirements on processes for the selective hydroge each case on the total amount of the active composition. In the nation of undesired unsaturated compounds are rising con context of this invention, "pure form' means that, apart from stantly. It is therefore an object of the invention to find an the copper (oxide), Zinc oxide, Zirconium dioxide and alumi improved process for selectively hydrogenating unsaturated num oxide fractions, no further constituents are present apart compounds, especially a process which avoids the formation 20 from insignificant constituents which are, for example, of by-products such as oxygenates. At the same time, activity entrained from the manufacture. Such as residues of starting and selectivity of the catalysts should be high. materials and reagents, assistants for shaping and the like. “Pure form” thus means that the active composition consists BRIEF SUMMARY OF THE INVENTION essentially of the components mentioned. 25 The percentages of the components of the active composi Accordingly, a process has been found for hydrogenating tion always add up to 100% by weight. unsaturated hydrocarbons over catalysts comprising copper Very suitable active compositions consist, in pure form, for and Zinc, which comprises using a catalyst whose active example of approx. 40% by weight of CuO, approx. 40% by composition, in unreduced form, consists essentially of from weight of ZnO and approx. 20% by weight of Al-O; of 10 to 95% by weight of copper oxide, calculated as copper(II) 30 approx. 70% by weight of CuO, approx. 20% by weight of oxide (CuO), from 5 to 90% by weight of zinc oxide (ZnO), ZnO and approx. 10% by weight of ZrO, or of approx. 70% optionally from 0.1 to 50% by weight of zirconium dioxide by weight of CuO, approx. 25% by weight of ZnO and (ZrO) and optionally from 0.1% by weight to 50% by weight approx. 5% by weight of Al-O, their proportions adding up of Al-O, the proportions by weight adding up to 100% by to 100% by weight. weight. 35 The active composition can, but need not necessarily, be applied to an inert Support. Suitable inert Supports are the DETAILED DESCRIPTION OF THE INVENTION known catalyst Supports, for example aluminum oxide, sili con dioxide, Zirconium dioxide, aluminosilicates, clays, Zeo The process according to the invention makes it possible to lites, kieselguhr and the like. It is equally possible to use hydrogenate unsaturated hydrocarbons in an economically 40 further known assistants for the processing of such as viable manner under mild conditions. The formation of oxy catalysts. Preference is given to using the active composition genates is avoided, as is the high capital tie-up in the case of without Support, i.e. active composition and catalyst are pref noble metal catalysts. Undesired overhydrogenation is erably identical. avoided; the process is suitable for the selective hydrogena Such catalysts are common commercial materials. Processes tion of alkynes in alkene streams. The catalyst is resistant to 45 for preparing such catalysts are known. A convenient and poisoning. preferred process comprises the following process steps in the The active composition of the catalyst to be used in accor sequence mentioned: dance with the invention comprises, in unreduced form, cop a) Preparation of a solution or Suspension of the components per oxides and Zinc oxides, and also optionally Zirconium of the catalyst and/or starting compounds thereof; oxides and aluminum oxides. Under reaction conditions, i.e. 50 b) precipitating a from this solution by adding a base, in the presence of reducing compounds such as hydrogen, optionally with mixing of the precipitation product with copper is present at least partly, but generally completely, in further components of the catalyst and/or of starting com the form of metallic copper. In the preparation of the catalyst, pounds thereof; it is typically obtained in the form of Cu(I) oxides and Cu(II) C) removing and drying the Solid; oxides; this is also the form of the catalyst which can be stored 55 d) optionally calcining the Solid; and transported without risk. e) shaping the Solid to tablets; and In pure form, the active composition of the catalysts to be f) optionally calcining the tablets; used in accordance with the invention generally comprises at least one of the two calcination steps d) or f) being per copper in an amount which, calculated as CuO, is at least 10% formed. by weight, preferably at least 20% by weight and more pref- 60 In the first process step, step a), a solution of the compo erably at least 30% by weight, and generally at most 95% by nents of the catalyst is prepared in a customary manner, for weight, preferably at most 85% by weight and more prefer example by dissolution in an acid Such as nitric acid. Option ably at most 80% by weight of copper oxide CuO, based in ally, instead of the components of the catalyst, their starting each case on the total amount of the active composition. In compounds are also used, for example the nitrates, carbon pure form, it generally comprises Zinc oxide ZnO in an 65 ates, hydroxycarbonates of the metals, are dissolved in an amount of at least 5% by weight, preferably at least 10% by aqueous solution which may also be acidic, for example a weight and more preferably at least 15% by weight, and nitric acid solution. The ratio of the salts in Solution is calcu US 8,680,350 B2 7 8 lated Stoichiometrically and adjusted according to the desired adjusted as usual, the BET surface area and the pore volume end composition of the catalyst. It is equally possible to add being known to fall with increasing calcination time and components in insoluble form, for example aluminum oxide, calcination temperature. as fine particles, and thus to obtain and to use a suspension in At least one of the two calcination steps is performed. which some components are dissolved and others are sus 5 Preference is given to calcining overall for at least a suffi pended. ciently long period that the content in the catalyst of carbonate From this solution, a Solid is precipitated in step b) as a (calculated as CO.) is at most 10% by weight, based on the precursor of the catalyst. This is done in a customary manner, total weight of the calcination product, and its BET surface preferably by increasing the pH of the solution by adding a area has a value in the range of at least 10 m?g, preferably at base, for instance by adding hydroxide Solution or 10 Sodium carbonate solution. least 30 m/g and, in a particularly preferred form, at least 40 The Solid precipitation product formed is generally m/g, in particular at least 50 m/g, and generally at most 100 removed from the supernatant solution before the drying in m?g, preferably at most 90 m/g and, in particularly pre step c), for instance by filtration or decanting, and washed ferred form, at most 80 m/g, in particular at most 75 m/g. with water to free it of soluble constituents such as sodium 15 The pore volume of the catalyst, measured as the water nitrate. It is equally possible to precipitate only some com uptake, is adjusted in the calcination to a value of at least 0.05 ponents of the catalyst or their precursors in this way, and to ml/g. These values are preferred for the catalyst to be used in mix the solid precipitation product with further, for example the process according to the invention. insoluble, components, for instance aluminum oxide. It is In the preparation of the catalyst, it will be appreciated that possible in principle to do this by mixing dried powders, but it is possible to use known assistants, for example pore form the mixing is preferably effected as a Suspension before ers or tableting assistants which decompose in the course of removal and drying of the precipitation product. calcination. The precipitation product (if appropriate mixed with fur The catalyst may also, as mentioned above, be deposited on ther insoluble components) is then normally dried with cus a Support. This is done by customary impregnation processes tomary drying methods before the further processing. Ingen 25 or precipitation processes. A precipitation process is known eral, a treatment at slightly elevated temperature is sufficient to be a precipitation process in the presence of a Support or of for this purpose, for instance about 80°C., preferably at least a Support precursor. To perform a precipitation process, pref 100° C. and more preferably at least 120° C., over a period of erence is given to adding a Support or support precursor in the from 10 minto 12 hours, preferably from 20 minto 6 hours precipitation process of the solution prepared in step a) and more preferably from 30 minto 2 hours. It is also possible 30 detailed above. If the support is already present in the form of and particularly convenient to convert the product of the preshaped finishing moldings, i.e. a pure impregnation pro precipitation directly—a certain alkali metal content, for cess is performed, the shaping step e) is dispensed with, example sodium content, of the catalyst is generally not dis otherwise the support is also formed in the course of the ruptive—or after washing by spray drying, to a dry powder processing of the precursor of the catalyst by precipitation, Suitable for further processing. 35 drying, calcination and shaping. After the drying, the precipitated and dried precursor of the A preferred precipitation process for preparing the catalyst catalyst is optionally subjected to the calcination step d). The is performed with preshaped supports and comprises the fol calcination temperature employed is generally at least 250 lowing process steps in the sequence mentioned: C., preferably at least 300° C. and more preferably at least a) preparing a solution of the components of the catalyst 350° C., and generally at most 500° C., preferably at most 40 and/or of Soluble starting compounds thereof. 450° C. and more preferably at most 410°C. The calcination b) impregnating a preshaped Support with this solution; time is generally at least 10 minutes, preferably at least 20 c) drying the impregnated Support; and minutes and more preferably at least 30 minutes, and gener d) calcining the impregnated and dried Support. ally at most 12 hours, preferably at most 6 hours and more Process step a) of this impregnation process is carried out preferably at most 4 hours. The drying step c) and the calci 45 like the above-described step a) of the precipitation process. nation step d) may merge directly into one another. In step b), a preshaped Support is impregnated with the solu After the drying step c) or the calcination step d), the tion. The preshaped Support has a shape selected correspond catalyst or its precursor is processed in shaping step e) by ing to the intended use, for example strands or extrudates, customary shaping processes such as extruding, tableting or tablets or pellets, including spherical pellets. The impregna pelletizing to moldings such as Strands or extrudates, tablets 50 tion is performed either with Supernatant solution or as an or pellets, including spherical pellets. impregnation with the amount of Solution corresponding to After the shaping step, the catalyst (i.e. to be more precise the pore volume of the support (“incipient wetness'). After its precursor) is optionally subjected to a calcination step f). the impregnation, the impregnated Support is dried and cal The calcination temperature employed here is generally at cined in steps c) and d) like the precipitation product in the least 300° C., preferably at least 350° C. and more preferably 55 precipitation process. Since a preshaped support is used, the at least 400°C., in particular at least 450° C. and generally at shaping step is dispensed with. most 700° C., preferably at most 650° C. and more preferably After the calcination, the catalyst is present in oxidic form, at most 600°C., in particular at most 580°C. The calcination i.e. the copper present therein is predominantly or exclusively time is generally at least 30 minutes, preferably at least 60 in the form of copper oxides. For the hydrogenation, the minutes, and generally at most 10 hours, preferably at most 3 60 catalyst has to be reduced, i.e. the copper has to be present hours and more preferably at most 2 hours, in particular at predominantly or exclusively in the metallic state. The reduc most 90 minutes. In a particularly preferred embodiment, the tion is effected by treating the oxidic catalyst present after temperature is increased slowly within the range mentioned calcination with a reducing agent. This can in principle be over the calcination time. done by any reducing agent which can reduce copper from the During the calcination steps, the catalyst precursor is con 65 I or II oxidation states to the 0 . The precise Verted to the actual catalyst and, among other parameters, the reaction conditions to be used are dependent upon the cata BET surface area and the pore volume of the catalyst are lyst, its precise state before reduction and upon the reducing US 8,680,350 B2 10 agent used, and can be determined easily in a few routine geneously catalyzed hydrogenation processes which serve experiments. Processes for reducing copper catalysts are the same purposes. They may be performed as heteroge known. neously catalyzed gas phase processes in which both the The reduction can be effected with liquid or dissolved hydrocarbon stream and the hydrogenating hydrogen are reducing agents; in this case, the reduction has to be followed present in the gas phase, or as a heterogeneously catalyzed by drying. It is therefore very much more convenient to gas/liquid phase process in which the hydrocarbon stream is reduce with a gaseous reducing agent, in particular to reduce present at least partly in the liquid phase and hydrogen is with hydrogen by passing over a hydrogen-comprising gas. present in the gas phase and/or in dissolved form in the liquid The temperature to be employed here is generally at least 80° phase. The parameters to be adjusted. Such as throughput of C., preferably at least 100° C. and more preferably at least 10 hydrocarbon stream expressed as Superficial Velocity in the 120° C., and generally at most 180° C., preferably at most 160° C. and more preferably at most 140° C. A suitable unit m3/m3*h'), based on the catalyst volume, temperature temperature is, for example, approx. 130°C. The reduction is and pressure, are selected analogously to those of known exothermic. The amount of reducing agent added should be processes. The temperature in the process according to the adjusted so as not to leave the selected temperature window. 15 invention is generally at least -50°C., preferably at least -10° The profile of the activation can be monitored with reference C. and, in particularly preferred form, at least 0°C., and to the temperature measured in the bed of the adsorbent generally at most 250° C., preferably at most 100° C. and, in (“temperature-programmed reduction, TPR'). particularly preferred form, at most 50° C. The pressure is A preferred method for reduction is, after a drying per generally at least 0.01 bar abs., preferably at least 0.8 bar abs. formed under a stream, to adjust the desired reduc and, in particularly preferred form, at least 1 bar abs., and tion temperature and to add a small amount of hydrogen to the generally at most 750 barabs., preferably at most 325 barabs. nitrogen stream. At the start, a suitable gas mixture com and, in particularly preferred form, at most 40 bar abs. prises, for example, at least 0.1% by volume of hydrogen in The amount of the hydrogen used, based on the amount of nitrogen, preferably at least 0.5% by volume and more pref the hydrocarbon stream fed, is dependent upon the content in erably at least 1% by volume, and at most 10% by volume, 25 the hydrocarbon Stream of undesired unsaturated compounds preferably at most 8% by volume and more preferably at most and their type. In general, the hydrogen is added in an amount 5% by volume. A suitable value is, for example, 2% by of from 0.8 up to 5 times the amount required stoichiometri Volume. This starting concentration is either retained or cally for complete hydrogen conversion in a reactor pass, increased in order to attain and to keep the desired tempera preferably in the range of from 0.95 to 2 times this amount. ture window. The reduction is complete when, in spite of 30 The hydrogenation of triple bonds normally proceeds more constant or rising level of the reducing agent, the temperature rapidly than the conjugated double bonds, and this in turn in the bed of the composition declines. A typical reduction more rapidly than the unconjugated double bonds. This time is generally at least 1 hour, preferably at least 10 hours allows appropriate control of the process with regard to the and more preferably at least 15 hours, and generally at most amount of hydrogen added. In special cases, for example 100 hours, preferably at most 50 hours and more preferably at 35 when high isomerization of 1-butene to cis- or trans-2-butene most 30 hours. is desired, it is also known that a relatively high hydrogen The drying, if required, is achieved by heating the catalyst excess, for example a ten fold hydrogen excess, can be used. to a temperature of generally at least 100° C., preferably at The hydrogen may comprise inert gases, for example noble least 150° C. and more preferably at least 180°C., and gen gases such as helium, neon or argon, other inert gases such as erally at most 300° C., preferably at most 250° C. and more 40 nitrogen, carbon dioxide and/or lower alkanes, for instance preferably at most 220°C. A suitable drying temperature is, methane, ethane, propane and/or butane. Such inert gases in for example, approx. 200° C. The precursor is kept at the the hydrogen are present preferably in a concentration of less drying temperature until only residues of adhering moisture than 30% by volume. Moderation of the catalyst by deliberate which are no longer troublesome are present; this is generally carbon monoxide addition is generally not required. the case for a drying time of at least 10 minutes, preferably at 45 The process can be performed in one reactor or in a plural least 30 minutes and more preferably at least 1 hour, and ity of parallel or series-connected reactors, in each case in generally at most 100 hours, preferably at most 10 hours and single pass or in circulation mode. When the process is per more preferably at most 4 hours. The drying preferably takes formed in the gas/liquid phase, the hydrocarbon stream, after place in a gas stream in order to transport the moisture away passing through one reactor, is typically freed of gases in a from the bed. To this end, for example, dry air can be used, but 50 separator, and some of the liquid obtained is recycled into the particular preference is given to flowing an inert gas through reactor. The ratio between recycled hydrocarbon stream and the bed; Suitable gases here are in particular nitrogenorargon. hydrocarbon stream fed for the first time into the reactor, Conveniently, the drying and the reduction are performed known as the reflux ratio, is adjusted such that the desired before the catalyst is used for the hydrogenation in the hydro conversion is achieved under the other reaction conditions, genation reactor, since transport and storage of the catalyst in 55 Such as pressure, temperature, throughput and amount of the reduced State entail particular safety measures and are hydrogen. difficult. However, the catalyst can also be reduced outside The purpose of using the process according to the invention the hydrogenation reactor, for instance by the catalyst manu is, for instance, the hydrogenation of alkynes to alkadienes, of facturer, and be passivated again by partial reoxidation by alkynes, alkynenes and alkadienes to alkenes, of phenyla customary processes in order to simplify transport and Stor 60 lkynes to phenylalkenes and/or of phenylalkenes to phenyla age. Before the use for the hydrogenation, it should then be lkanes. completely reduced again. These measures are common and Examples of applications of the process according to the generally known for copper catalysts. invention are those: The hydrogenation process according to the invention is for the selective hydrogenation of acetylene in C2 streams to notable by the use of the above-described catalyst. The hydro 65 ethylene with minimal formation of ethane (this embodiment genation process according to the invention using the catalyst of the process is referred to hereinafter as “process A' for described is generally performed just like the known hetero simplification), US 8,680,350 B2 11 12 for the selective hydrogenation of propyne and/or propadiene obtained as the product of value) or a selective “tail-end in C3 streams to give propylene with minimal formation of vinylacetylene hydrogenation' after the butadiene extraction propane (“process B), from the C4 stream. for the selective hydrogenation of 1-butyne, 2-butyne, 1.2- Process E is performed preferably as a gas/liquid phase butadiene and/or vinylacetylene in C4 streams to give 1.3- process with a superficial velocity of the liquid C5+ stream of butadiene, 1-butene, cis- and/or trans-2-butene (“process C), from 0.5 m/mh, based on the catalyst volume, to 30 for the selective hydrogenation of 1-butyne, 2-butyne, 1.2- m/mh at a temperature of from 0° C. to 180° C. and a butadiene, 1,3-butadiene and/or vinylacetylene in C4 streams pressure of from 2 bar to 50 bar, from one to two moles of to give 1-butene, cis- and/or trans-2-butene, in butadiene-rich hydrogen being added per mole of compounds to be hydro C4 streams (“crude C4 cut”) or low-butadiene C4 streams 10 genated in the C5-- stream. Process E can be used, for (“raffinate I) (“process D'), and example, as a selective pyrolysis gasoline hydrogenation, as a for the selective hydrogenation of unsaturated compounds selective hydrogenation of olefins in reformate streams or coking oven condensates, for the hydrogenation of pheny and/or unsaturated Substituents of aromatic compounds in lacetylene to styrene or for the hydrogenation of Styrene to C5+ streams to more highly saturated compounds and/or 15 aromatic compounds having more highly saturated Substitu ethylbenzene. ents with minimal hydrogenation of the aromatic rings (“pro cess E). EXAMPLES in each case using the above-described catalysts. Process A is performed typically as a gas phase process Examples 1 to 4 with a superficial velocity of the gaseous C2 stream of from 500 m/mh, based on the catalyst volume, to 10 000 m/mh at a temperature of from 0° C. to 110° C. and a Preparation of Catalysts A-D pressure of from 0.01 bar to 50 bar, one mole of hydrogen being added per mole of acetylene in the C2 stream. 25 A heatable 101 precipitation vessel equipped with a stirrer Process B is performed typically as a gas phase process or was initially charged in each case with 1.2 1 of water and as a gas/liquid phase process with a Superficial velocity of the heated to 70° C. Subsequently, metal nitrate solutions in nitric liquid C3 stream of from 1 m/mh, based on the catalyst acid were in each case metered in with stirring in the amounts volume, to 50 m/mhat a temperature of from 0° to 50° C. needed to achieve the composition, specified below in Table and a pressure of from 0.01 bar to 50 bar, from one to two 30 1, of the catalysts A-D thus prepared. At the same time, a 20% moles of hydrogen being added per mole of propyne and by weight sodium carbonate solution was metered in Such that propadiene in the C3 stream. a pH of 6.5 was maintained in the precipitation vessel. The Process C is performed typically as a gas/liquid phase suspensions formed were stirred at 70° C. and pH 6.5 for 120 process with a superficial velocity of the liquid C4 stream of minutes, then filtered off and washed with cold water to free from 1 m/mh, based on the catalyst volume, to 50m/mh 35 them of nitrate (<25 ppm of nitrate in the effluent). The at a temperature of from 0°C. to 180° C. and a pressure of filtercakes were dried, then calcined at 300° C. over 4 hours from 2 bar to 50 bar, from one to two moles of hydrogen being and then tableted. added per mole of butyne, 1,2-butadiene and vinylacetylene In the case of catalysts A and B, another calcination step in the C4 stream. Process C can be used, for example, as a was performed after tableting. selective “front-end vinylacetylene hydrogenation' before a 40 butadiene extraction. TABLE 1 Process D is performed typically as a one- or two-stage gas/liquid phase process with a Superficial Velocity of the Composition, in each case in 96 by weight, liquid C4 stream in the range of from 0.1 m/mh, based on of the catalysts of Examples 1-4 the catalyst volume, to 60 m/mh, preferably of from 1 45 m/mh to 50 m/mh, at a reactor entrance temperature in Example No. Catalyst CuO ZnO Al2O3 ZrO2 the range from 20° C. to 90° C., preferably from 20° C. to 70° 1 A. 40 40 2O 2 B 70 2O 10 C., and a pressure in the range of from 5 bar to 50 bar, 3 C 40 40 2O preferably from 10 bar to 30 bar, one mole of hydrogen being 4 D 70 25 5 added per mole ofbutyne, butadiene and vinylacetylene in the 50 C4 stream. For example, the process is performed in two stages, in which case the butadiene content, which, in typical C4 streams from steamcrackers, is in the range from 20% by Examples 5 to 8 weight to 80% by weight, based on the overall stream, is reduced in the first stage down to a content in the range of 55 from 0.1% by weight to 20% by weight, and, in the second Hydrogenation of Acetylene in a C2 Stream stage, down to the desired residual content in the range from a few ppm by weight to about 1% by weight. It is equally Samples of the tablets obtained in Example 1 were reduced possible to divide the overall reaction between more than two with hydrogen and then contacted in a tubular reactor with a reactors, for example three or four. The individual reaction 60 C2 stream (ethylene, mixed with the proportions of hydrogen stages may be operated with partial recycling of the hydro and acetylene specified in Table 2 below) at a superficial carbon stream; the reflux ratio is typically in the range from 0 velocity (GHSV) of 2300h' and the temperature specified in to 30. When process D is performed, isobutene remains the table. The pressure set was ambient pressure, i.e., essentially unchanged and can be removed from the C4 upstream of the reactor, only the pressure needed to overcome stream by known methods before or after the performance of 65 the pressure drop of the apparatus was set. The proportions of process D. Process D can be used, for example, as abutadiene hydrogen and acetylene measured downstream of the reactor hydrogenation in the C4 stream (when butadiene is not to be are specified in Table 2 below. US 8,680,350 B2 13 14 TABLE 2 optionally from 0.1% by weight to 50% by weight of Al-O. Hydrogenation of acetylene the proportions by weight adding up to 100% by weight, Upstream Downstream wherein hydrogenation is effected at a temperature of at of reactor of reactor 5 most 50° C. Example Temp. ppm by volumel ppm by volume 2. The process according to claim 1, wherein the catalyst in No. Catalyst C. H2 C2H2 H2 C2H2 unreduced form, consists essentially of from 20 to 85% by weight of copper oxide, calculated as 5 A. 100 S8O 376 <10 <2 6 B 25 959 62O 6 <2 10 copper(II) oxide (CuO), 7 C 25 741 705 50 <2 from 10 to 80% by weight of zinc oxide (ZnO), 8 D 25 638 681 37 7 from 3 to 40% by weight of zirconium dioxide (ZrO) and optionally from 3% by weight to 40% by weight of Al-O. Examples 5-8 show that acetylene in a C2 stream can be the proportions by weight adding up to 100% by weight. removed virtually completely at very low temperatures by the 15 3. The process according to claim 2, wherein acetylene in process according to the invention. an ethylene stream is hydrogenated. 4. The process according to claim 2, wherein propyne and Examples 9-11 allene in a propylene stream are hydrogenated. 5. The process according to claim 1, wherein the catalyst in Hydrogenation of Propyne 2O unreduced form, consists essentially of from 30 to 80% by weight of copper oxide, calculated as Samples of the tablets obtained in Example 1 were reduced copper(II) oxide (CuO), with hydrogen and then contacted in an autoclave at a pres from 15 to 70% by weight of zinc oxide (ZnO), sure of 20 bar and 25° C. over 2 hours with liquid propene from 5 to 30% by weight of zirconium dioxide (ZrO) and (CH) which had been admixed with 120 ppm by weight of 25 optionally from 3% by weight to 30% by weight of Al-O. propyne (CH) and 450 ppm by weight of hydrogen. The the proportions by weight adding up to 100% by weight. propene further comprised 300 ppm of propane (CHs). 6. The process according to claim 5, wherein acetylene in The proportions of hydrogen, propane and propyne which an ethylene stream is hydrogenated. were measured subsequently are reported in Table 3 below. 7. The process according to claim 5, wherein propyne and 30 allene in a propylene stream are hydrogenated. TABLE 3 8. The process according to claim 1, wherein acetylene in Hydrogenation of propyne in propene an ethylene stream is hydrogenated. 9. The process according to claim 1, wherein propyne and After reaction ppm by weight 35 allene in a propylene stream are hydrogenated. Example No. Catalyst CHs CH 10. The process according to claim 1, wherein hydrogena 9 B 310 330 tion is effected at a temperature of at most 25°C. 10 C 382 310 11. The process according to claim 1, wherein Al2O is 11 D 340 510 present in the catalyst. 40 12. The process according to claim 1, wherein the catalyst Examples 9-11 show that the virtually complete removal of in unreduced form, consists essentially of propyne in C3 streams is possible in a highly selective manner from 40 to 70% by weight of copper oxide, calculated as at comparatively low temperatures by the process according copper(II) oxide (CuO), to the invention. from 20 to 40% by weight of zinc oxide (ZnO), The invention claimed is: 45 from 5 to 30% by weight of zirconium dioxide (ZrO) and 1. A process for hydrogenating alkynes in C2 or C3 streams optionally from 5% by weight to 20% by weight of Al-O. which comprises hydrogenating the alkynes over the catalyst and whose active composition, in unreduced form, consists essen the proportions by weight adding up to 100% by weight. tially of 13. The process according to claim 12, wherein Al-O is from 10 to 95% by weight of copper oxide, calculated as 50 present in the catalyst. copper(II) oxide (CuO), 14. The process according to claim 1, wherein the copper from 5 to 90% by weight of zinc oxide (ZnO), oxide is presentina weight percent equal to or greater than the from 0.1 to 50% by weight of zirconium dioxide (ZrO2) weight percent of the Zinc oxide. and k k k k k