Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C5/00—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms
  • C07C5/32—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by dehydrogenation with formation of free hydrogen
  • C07C5/327—Formation of non-aromatic carbon-to-carbon double bonds only
  • C07C5/333—Catalytic processes
  • C07C5/3332—Catalytic processes with metal oxides or metal sulfides
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
  • B01J23/76—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
  • B01J23/84—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
  • B01J23/85—Chromium, molybdenum or tungsten
  • B01J23/86—Chromium
  • B01J23/862—Iron and chromium

Definitions

• This invention relates generally to 5 catalysts particularly useful for the production of olefins by dehydrogenatin and more specifically to the composition and method of manufacture and use of improved dehydrogenation catalyst. 10 Considerable research has been directed in the past toward improving the production of olefins by dehydrogenation. Background Art
• Steam active dehydrogenation catalysts 15 are widely used in the dehydrogenation to olefins and diolefins, e.g., butanes to butadienes; alkyl aromatics to alkenyl aromatics, e.g., ethylbenzene to styrene.
• olefins and diolefins e.g., butanes to butadienes
• alkyl aromatics to alkenyl aromatics, e.g., ethylbenzene to styrene.
• Various catalysts and the dehydrogenation 20 conditions and other operating data are disclosed in Pitzer, U.S. Patent Nos. 2,866,790 and 2,866,781; Gutzeit, U.S. Patent No. 2,408,140, and Eggertsen, et al., U.S.
• Patent No. 3,360,579 and Sie U.S. Patent
• Pitzer discloses a catalyst where the catalyst which contains about 50% K-CO-., up to 10% Cr_0, and the balance Fe*® ? is heat treated at at least 1000 degrees or
• the steam active alkalized iron dehydrogenation catalysts disclosed in these patents contain various amounts ' of iron oxide and potassium carbonate with a minor but effective amount of chromium oxide incorporated therein as a stablizer or structural promoter.
• Facilities for dehydrogenation are advantageously operated at the highest practical throughput rates and small improvements in selectivity and activity of dehydrogenation catalyst can result in substantial savings.
• SUBSTITUTE SHEET ⁇ IP high selectivity and high activity because generally, high selectivity is accompanied by low activity and vice versa.
• Activity, of the catalyst is defined as the percent of the starting material, e.g., ethylbenzene, which is converted from the original state during the dehydrogenation process.
• Selectivity of the catalyst is defined as the ratio of the amount of the desired product produced in the process, for example styrene, to the total feedstock converted.
• a high conversion by catalytic dehydrogenation is generally favored by a high temperature and a low pressure.
• dehydrogenation of ethylbenzene to styrene there are also undesirable side reactions which simultaneously occur to produce benzene and toluene.
• the side reactions go to completion and are not limited by equilibrium considerations.
• the benzene produced can be recycled for later processing but the toluene cannot and must be disposed of. Accordingly, in the evaluation of a system where the. by products are produced, the production of benzene as opposed to toluene is preferred.
• the present invention provides a new and useful catalyst for the production of olefinic
• the present invention also provides a method for production of a catalyst for the dehydrogenation of ethylbenzene to styrene at low steam to oil ratios where the catalyst maintains stability at lower steam/oil ratios and where, unexpectedly, the relative production of toluene is substantially diminished over a wide range of steam/oil weight ratios.
• catalysts in accordance with the present invention provide longer operating periods between regeneration cycles even at lower steam/ oil ratios and reaction temperatures. It has been further found that catalysts provided by the present invention unexpectedly
• SUE S T ⁇ TUTE SHEET provide good activity and selectivity in the dehydrogenation of diethylbenzene ethyltoluene, propylbenzene, butylbenzene and other alkyl substituted benzenes.
• the present invention provides a catalyst found to be particularly effective in the dehydrogenation of ethylbenzene, diethylbenzene, and ethyltoluene, to olefinic compounds or
• the catalysts includes iron oxide, at least 20% by weight alkali water gas promoter and at least 1.0% by weight chromium oxide where the catalyst is formed into pellets of selected configuration
• Figure 1 is an illustration of a Mercury Porosimetry Evaluation of a catalyst within the scope of the present invention
• FIG 2 is an illustration of the result of a Mercury Porose itry Evaluation of a comparison catalyst calcined in accordance with the present invention
• Figure 3 is an illustration of the result of Mercury Porosimetry Evaluation of a catalyst within the scope of the present invention and one having the same composition but calcined for a different length of time
• Figures 4a-4b are comparative illustrations of selectivity of a catalyst within the scope of the present invention and a prior art catalyst calcined for a longer time at higher temperatures
• Figure 5 is a comparison of a catalyst shown in Figure 1 illustrating benzene/ toluene ratios in the effluent
• Figure 6 is a graphic illustration of the conversion or activity of the catalysts of Figures 4a-4b over a period of time.
• the method of the present invention provides a dehydrogenation catalyst including iron oxide, at least 25% by weight of potassium carbonate and at least 1.3% by weight chromium oxide.
• the composition is formed into pellets of selected size and heat treated at 950 degrees to 1100 degrees for 15 minutes to 8 hours to provide the pore volume characteristics found to be beneficial in the subject invention, in that the catalyst unexpectedly yields excellent selectivity and longer catalyst life at lower steam to oil ratios, all as discussed hereinafter.
• the iron oxide customarily is of pigmentary grade but may also be prepared by the thermal decomposition of ferric nitrate, ferric oxalate, ferrous sulfate and the like.
• the iron oxide in the finished catalyst is usually in the alpha form.
• the iron oxide may constitute up to 53.5% by weight of the catalyst but is preferably within the range from about 25% to about 45%.
• One example of a catalyst of the present invention was prepared with the following analysis by dry mixing the necessary ingredients and calcining at 1000-1100 ⁇ F for 2 hours:
• the concentration of alkali water gas promotor may vary from 20% to 55% and the proportion of chromium oxide may vary from 1.3% to 5.0% with the balance of the composition iron oxide.
• the catalyst represented by curve A was calcined in air at 1100 degrees for 24 hours.
• the catalyst represented by curve 3 was calcined in accordance with the present invention at 15 900 degrees 1100 degrees for 2 hours.
• the steam to oil (or feedstock) ratio was varied between 6:1 to 0.6:1 by weight as described hereinafter at liquid hourly space velocity (LHSV) of 1.0 to 2.0 as indicated hereinafter.
• LHSV liquid hourly space velocity
• Table I illustrates that even in an extended heat run, reaction conditions can be modified then returned to initial conditions without adverse effect on catalyst performance.
• Table II provides the results of tests to demonstrate performance of the invention catalyst and the aforementioned comparison catalyst in the dehydrogenation of diethylbenzene (DEB) to divinylbenze (DVB) and ethylvinyl benzene (EVB) at the indicated conditions.
• DEB diethylbenzene
• DVD divinylbenze
• EVB ethylvinyl benzene
• reaction temperature was varied stepwise between 1050°F; 1100° F; and 1150°F; steam/oil ratio varied from 2.5:1 to 6.0:1 and pressure varied from OPSIG to PSIG.
• steam/oil ratio varied from 2.5:1 to 6.0:1
• pressure varied from OPSIG to PSIG.
• catalyst in accordance with the present invention is useful in dehydrogenation of ethylbenzene to styrene and unexpectedly provides improved characteristics as described hereinafter.
• Table III is a tabulation of the results of the dehydrogenation of ethylbenzene to styrene over the invention catalyst previously described at the conditions noted.
• Figure 4a graphically illustrates the selectivity of ethylbenzene conversion to styrene using the catalyst of the invention - at indicated steam/oil ratios by weight while Figure 4b indicates selectivity for the comparison catalyst.
• Figure 5 is a graphic representation of the benzene/toluene ratio for selected conditions utilizing the catalyst of the
• Figure 6 illustrates one of the unexpected advantages of the present invention; that is that the difference between the conversion rate of the catalyst diminishes with lower steam oil ratios and the catalyst of the present invention provides satisfactory and stable conversion at steam/oil ratios of 0.8 and 0.6 over an extended period of time where the comparison catalyst becomes unsatable at 1.0 S/O.
• this advantage is important because the lower steam/oil ratios permit energy cost savings.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
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• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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• 1982
  • 1982-08-17 WO PCT/US1982/001120 patent/WO1983000687A1/en not_active Application Discontinuation
  • 1982-08-17 EP EP19820903004 patent/EP0085718A4/de not_active Withdrawn
  • 1982-08-17 JP JP57502980A patent/JPS58501272A/ja active Pending

Non-Patent Citations (2)

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