DE1593641B - Process for the selective catalytic hydrogenation of conjugated diolefins to the corresponding monoolefins - Google Patents

Description

Process for the selective catalytic hydrogenation of conjugated diolefins to the corresponding Monoolefins.

Three of the main types of catalysts commonly used for the selective hydrogenation of conjugated diolefins used for monoolefins are:

1. Palladium catalysts, which have the disadvantage that they are insufficiently selective (a too large conversion into saturated hydrocarbons) and the sulfur-free starting materials must be used;

2. Catalysts based on metal sulfides, such as. B. the sulphides of nickel, cobalt and Molybdenum, which has the defect that harsh and expensive working conditions are used have to be and

3. Copper chromite catalysts, which the shortcomings. possess that they are insufficiently selective that sulfur-free starting materials must be used and that fairly hard pressure and Temperature conditions are required.

The use of platinum metal sulfides, ie the sulfides of ruthenium, rhodium, palladium, osmium, iridium and platinum, as catalysts for certain hydrogenation reactions is already known from Belgian patent specification 643 911. The platinum metals are the six metals (listed above) in Group VIII of the 5th and 6th Periods of the Periodic Table. The term “precious metals” is often used not only to refer to the six metals mentioned, but also to gold and silver. To avoid misunderstandings, it should be noted that the term "platinum metals" is used to denote the six metals listed above, as understood by those skilled in the art of catalysis. (Encyclopedia of Chemical Technology, Vol. 10, pp. 819 to 859 [Interscience, 1953].)

According to the present invention, the use of certain sulphides of the platinum metals as Heterogeneous hydrogenation catalysts for the reduction of diolefins to monoolefins have been proposed.

The catalysts used according to the invention have compared to the catalysts known hitherto the most diverse advantages.

First, these catalysts have a level of selectivity that has previously been achieved in the hydrogenation of Diolefins was unreachable.

Second, these platinum metal sulfide catalysts are also in the presence of those sulfur-containing compounds relatively effective, severely poisoning most other catalysts. So can sulfur-containing starting materials are used in the catalysts of this invention, and the use of purified hydrogen is not required. The platinum metal sulfide catalysts can can even be used for the hydrogenation of compounds containing one or more sulfur atoms in the Molecule included. Their relatively great insensitivity to sulfur vouches for one long lifespan at a high level of activity, even if in contact with sulfur for a long time come.

The poisoning of the usual hydrogenation catalysts by compounds containing sulfur, hydrogen sulfide or other sulfur groups, that work even in small amounts is dealt with in many scriptures, such as: Am Journal of the American Chemical Society, Vol. 70, p. 1392 (1948); "Reactions of Hydrogen with Organic Compounds "by H. A d k i η s (University of Wisconsin Press, 1937), p. 22; "Catalysis" by Berkman.Morrell and E g 1 o f f (Reinhold Publishing Corp., 1940), pp. 391 to 393. The poisoning more specific Copper and Raney nickel catalysts are described in "Industrial & Engineering Chemistry", Vol. 52, p. 417 (1960), and Vol. 33, p. 1373 (1941).

Third, the platinum metal sulfide catalysts are far more active than that for many hydrogenation reactions previously known metal sulfide catalysts, and therefore they are suitable for reactions to avoid unwanted side reactions are carried out at relatively low temperatures have to.

Fourth, the catalysts of the invention also have the economic advantage that they are at relatively low pressures are effective.

The platinum metal sulfide catalysts can be produced by a wide variety of reactions. Such reactions are: conversion of corresponding compounds of metals (e.g. OsO ₄ , IrCl ₃ ) with solutions of alkali, alkaline earth or ammonium sulfides, hydrosulfides or polysulfides; Treatment of solutions of suitable compounds of the metals (e.g. H ₂ PtCl ₆ · H ₂ O, PdCl ₂ · 2H ₂ O) in dilute acids with hydrogen sulfide; Reaction of the metal itself with hydrogen sulfide, other sulfur-containing compounds or elemental sulfur; and generally any process known to a person skilled in the art of preparing catalysts. The catalyst can be prepared in situ or prefabricated, that is, it can be added to the hydrogenation reaction mixture after prior preparation and isolation. Furthermore, the catalyst can be used as a loose powder or applied to a suitable carrier, such as. B. carbon or aluminum oxide can be used. Furthermore, whether it is applied to a carrier or not, it can be in the form of a powder for reactions in which the catalyst is slurried in the liquid phase or atomized in the vapor phase, or in the form of pellets for reactions in the liquid phase or Vapor phase can be used with a resting catalyst bed.

The used in the process of the invention, the sulfides of platinum, palladium and Ruthenium-containing catalysts can be obtained by those described in Belgian patent 643 911 Process are produced.

The invention is based on the object of a catalytic process for the selective hydrogenation of conjugated diolefins to create the corresponding monoolefins, with only a small or negligible one Part of the corresponding saturated hydrocarbons is formed. Another job is to a catalytic process for the removal of diolefins from olefinic starting materials, the currently used in gasoline manufacture and in polymerization processes, and in particular to provide a method for removing 1,3-butadiene from butene.

Another object is to provide a hydrogenation process using such catalysts to create, which have a high selectivity, do not require sulfur-free starting materials and

are effective under very mild pressure and temperature conditions.

The process according to the invention for the catalytic selective hydrogenation of conjugated diolefins to the corresponding monoolefins is characterized in that the catalyst used is platinum sulfide, palladium sulfide or ruthenium sulfide and the reaction is carried out at a temperature of 50 to 350 ° C. and a pressure of 3.5 to 70 kg / cm ² .

Conjugated diolefins which can be selectively hydrogenated by the present process are e.g. B .: acylic compounds such as 1,3-butadiene, 1,3-pentadiene (Piperylene), 2-methyl-1,3-butadiene (isoprene) and 2,3-dimethyl-1,3-butadiene, and cyclic compounds such as 1,3-cyclopentadiene, 1-methyl-4-isopropyl-1,3-cyclohexadiene (alpha-terpinene), l-methyl-5-isopropyl-1,3-cyclohexadiene (alpha-phellandren) and 1,3-cyclooctadiene. Due to the presence of sulfur or from sulfur compounds in the starting materials, the catalyst of the invention will not deactivated or poisoned.

The preferred temperature range is between 100 and 200 ° C.

The preferred pressures are in the range from 3.5 to 35 kg / cm ² .

The exact process conditions depend of course on the type of hydrogenation reaction to be carried out as well as on the optimal economic one Combination of temperature, pressure, amount of catalyst and reaction time. As from the examples can be determined by extrapolation, such low weight ratios of catalyst (in pure form or as a supported catalyst) to reactants to be hydrogenated, such as 0.001 quantitative or almost quantitative conversions.

When a hydrogenation process is operated continuously, the amount of catalyst is better expressed as the weight of hourly feed per weight of catalyst (space velocity). When practicing the present method, the space velocity can be in the range from about 0.1 to 100, with a range of from about 0.5 to 25 being preferred. Also hang here the exact working conditions of the optimal combination of pressure, temperature and space velocity away.

The reactions can either be batchwise or continuous, bowl-shaped or tubular Reactors are running. You can also use slurried in the liquid phase or dormant catalysts or in the vapor phase with atomized or dormant catalysts the procedures known in the art can be carried out. When the implementation in the liquid Phase, it may be desirable to use an inert solvent to control the heat of reaction to use. Any non-reactive solvent in which the feed is reasonably is soluble can be used.

The invention is illustrated in more detail by the following examples.

B e i s ρ i e 1 1

Liquid butadiene was passed through from a stainless steel reservoir calibrated positive piston pump. Both the reservoir and the pump were kept at a temperature below -15 ° C. The hydrogen was taken from a commercially available bomb. Its flow rate was controlled by a needle valve and measured by a calibrated flow meter. the Total pressure was controlled by a back pressure valve.

Hydrogen and butadiene flowed into the same block and then into the reactor. The reactor passed from a 50.8 cm long and 25.4 mm wide tube made of corrosion-resistant steel and had five Silver soldered thermal pockets and high pressure connections at both ends. The first were 10 inches filled with corrosion-resistant steel wool and served as a preheater. This was followed by one 20.3 cm long catalyst zone. The preheat and catalyst bed zones had separately controlled ones ribbon-shaped heaters. In addition, the catalyst zone was surrounded by a jacket for water cooling.

The products were placed in a stainless steel receptacle at approximately -40 ° C condensed and collected.

In Runs A through C the catalyst zone was with 100 ml (approximately 90 g) 3.2 mm catalyst pellets filled. In Runs D through I, the catalyst zone contained 10 ml (approximately 9 g) 3.2 mm Catalyst pellets that were in the center of the catalyst zone with the remainder of the catalyst zone was filled with glass beads on both sides. A thermocouple was located in the center of the catalyst bed. In Experiment J, the 10 ml of catalyst pellets were replaced by 10 ml (approximately 3 g) of a powdered one Replaced the catalytic converter.

The results are shown in Table I. The analytical values were obtained by gas-liquid chromatography receive.

Table I Hydrogenation of Butadiene

catalyst temperature pressure Flow rate
Moles / min. Butadiene Around
Wall
lung Yield 1 percent (- ^/ ') Space- Ver
search-
number ⁰ C kg / cm ² hydrogen 0.0026 butane Butene speed,
Butadiene
gew / kata- 0.5% Pt on aluminum 41 7th 0.10 100 99 1 Iy Siitor ~
w / h A. oxide (") 0.0026 0.925 74 7th 0.10 0.0026 100 100 0 B. 48 3.5 0.10 94 82 18th 0.925 C. 0.925

⁽ "| Approximately 90 g 3.2 mm pellets.

^1/1 based on converted butadiene. All Armlysenwcrtc were obtained by gas-liquid chromatography.

continuation

catalyst temperature pressure Flow rate Butadiene Around yield Mole percent Space- Ver Moles / min. 0.010 Wall speed. search- '' C kg / cnr 0.010 lung butane Butene Butadiene number 0.1% Pt on aluminum 69 7th hydrogen 0.0064 33 67 gew / kata- oxide ( ^h - ^c ) 78 7th 0.10 0.0064 8th 28 '72 1 jradlUI
w / h D. 0.5% Pt sulfide 210 7th 0.10 0.013 19th 0 100 3.6 E. Aluminum oxide ^ ¹ *) 221 to 232 7th 0.14 0.013 13th track about 100 3.6 F. 0.5% Pd sulfide 201 7th 0.14 0.013 73 0 100 2.3 G Aluminum oxide ( ^w ) 207 to 214 7th 0.14 7th 0 100 2.3 H 5% Ru sulfide 194 7th 0.14 19th 0 100 4.7 I. Carbons ^{1 6} ) 0.14 8th 4.7 J 14.1

^w Approximately 9 g of 3.2 mm pellets.

^(c) Poisoned by 0.02 moles of thiophene per mole of butadiene in the butadiene starting material.

^(d> Feed contained 5 x 10 -4 * moles / min of hydrogen sulfide to keep the catalyst in a sulfided state.

^(e> About 3 g of powdered catalyst.

The ratios of 2-butenes to 1-butene were much lower than the equilibrium values (J. E. K i 1 ρ a t r i c k, E. J. Prosen, K. S. P i t ζ e r and F. D. R ο s s i η i, J. Res. Natl. Bur. Standards, Vol. 36; P. 559 [1946]), from which it emerged that 1-butene was formed as the primary product.

The desired selectivity in Example 1 is the conversion of butadiene to butenes under one minimal butane formation.

Experiments A to C show a very weak selectivity for platinum. As expected, decreased the rate, measured as butadiene conversion, with decreasing hydrogen pressure while at the same time the selectivity increased (see. Experiments A and C); however, it was still quite weak.

Experiments D and E with a partially sulfur-poisoned platinum show that the poisoning increases the selectivity of platinum noticeably improved; but the selectivity was nowhere near sufficient. the The phenomenon of increasing selectivity as a result of partial poisoning is well known in the art.

Experiments F and G show complete selectivity for platinum sulfide. All of the butadiene converted was converted into butenes, with little or no butane being formed. The order of selectivity is platinum sulfide »poisoned platinum> platinum. The large difference in activity, as reflected in the working temperatures, between the sulphided catalyst (experiments F and G) and the unsulphided catalysts, both ( _v / j poisoned (experiments D and E) and non-poisoned (experiments A to C)) is considerable .

Experiments H and I show complete selectivity for palladium sulfide. Experiment J shows complete selectivity for ruthenium sulfide.

Example 2

Each experiment was carried out with 0.10 moles of monoolefin or diolefin, 55 ml of pentane (as solvent) and 1.85 g of a carbon-supported catalyst with 5% platinum sulfide in a stainless steel autoclave. After the above compounds had been introduced, the autoclave was closed and then flushed first with nitrogen and then with hydrogen. Hydrogen was then injected up to the desired pressure and the reaction mixture was heated with stirring. After the reaction had ended, the autoclave was cooled and vented, whereupon the reaction product was discharged. The catalyst was removed by filtration and the products were quantitatively analyzed by gas-Ci liquid chromatography. The results are shown in Table II. The first experiment in Part B shows particularly well the selective hydrogenation of the conjugated diolefin 1,3-cyclohexadiene to the monoolefin cyclohexene, with only very little conversion to the saturated hydrocarbon cyclohexane.

Table II

Starting olefin

pressure

kg / cm ²

Time during which the temperature was maintained hours of cyclohexadiene

Yield, mole percent

Cyclohexene

Cyclohexane

Part A - 140 ⁰ C
1,3-cyclohexadiene
Cyclohexene .......

Part B-IlO ⁰ C
1,3-cyclohexadiene
Cyclohexene

Part C-110 ⁰ C.
1,4-cyclohexadiene

43.75 to 52.50
50.40 to 53.90

11.20 to 19.60
19.95 to 20.65

18.65 to 20.30

V ₂ 1

3V ₂ 3V ₂ 0 0

4th 0

81 *)

93
63

95
93

7th 37

*) Of the 81 parts remaining as cyclohexadiene, 4 parts were converted into 1,3-cyclohexadiene.

The numbers in Part A of Table II show that at fairly high temperatures and pressures, the removal of the conjugated diolefin 1,3-cyclohexadiene from the feed is quantitative with only 7% of the feed to be converted to the saturated cyclohexane. The comparison test shows that only 37% of the pure cyclohexane feed converted into the saturated cyclohexane in twice the time will.

The numbers in Part B show that at economically low temperatures and pressures, the removal of the conjugated diolefin 1,5-cyclohexadiene from the feed is almost quantitative (96% yield) _{in 3–2 hours.} A little more than 1% of the original diolefin is converted into the saturated cyclohexane. In the comparative experiment, only 7% of the pure cyclohexene charge (at a slightly higher pressure) is converted into the saturated cyclohexane.

The figures in Part C show that although the educated The amount of cyclohexane is 18 times the amount of saturated cyclohexane formed, only about 19% of the unconjugated diolefin 1,4-cyclohexadiene is reduced at all. (Approximately 4% of the original diolefin feed is converted from 1,4-diene to 1,3-diene.) This shows that the non-conjugated diolefin shows that the non-conjugated diolefin shows that it is very slow reacted with the catalyst of the present invention.

Claims (8)

Patent claims: 1. A process for the selective catalytic hydrogenation of conjugated diolefins to the corresponding monoolefins, characterized in that the catalyst used is platinum sulfide, palladium sulfide or ruthenium sulfide and the reaction at a temperature of 50 to 350 ° C and at a pressure of about 3.5 to 70 kg / cm ² . 2. The method according to claim 1, characterized in that that one uses 1,3-cyclohexadiene or butadiene as the diolefin. 3. The method according to any one of the preceding claims, characterized in that one carries out the reaction at a temperature of 100 to 200 ⁰ C. 4. The method according to any one of the preceding claims, characterized in that the reaction is carried out at a pressure of about 3.5 to 35 kg / cm ² . 5. The method according to any one of the preceding claims, characterized in that one Catalyst to diolefin weight ratio of at least 0.001 applies. 6. The method according to any one of the preceding claims, characterized in that the Carries out reaction continuously. 7. The method according to any one of the preceding claims, characterized in that the diolefin with the catalyst at a quantitative hourly space velocity (Weight of hourly feed per weight of catalyst) from 0.1 to 100 in contact is brought. 8. The method according to any one of the preceding claims, characterized in that one applies quantitative hourly space velocity of 0.5 to 25. 009 550/394