Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
  • C07C45/27—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation
  • C07C45/32—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen
  • C07C45/33—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen of CHx-moieties
  • C07C45/34—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen of CHx-moieties in unsaturated compounds
  • C07C45/35—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen of CHx-moieties in unsaturated compounds in propene or isobutene
• • 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
  • B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
  • B01J27/02—Sulfur, selenium or tellurium; Compounds thereof
  • B01J27/057—Selenium or tellurium; Compounds thereof
  • B01J27/0576—Tellurium; Compounds thereof
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
  • C07C51/16—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation
  • C07C51/21—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen
  • C07C51/25—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of unsaturated compounds containing no six-membered aromatic ring
  • C07C51/252—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of unsaturated compounds containing no six-membered aromatic ring of propene, butenes, acrolein or methacrolein

Definitions

• the single phase process is preferred.
• a great variety of catalysts may be used in that process.
• the primary object of the present invention is to provide a process for oxidizing the unsaturated alpha-beta olefins to the corresponding unsaturated aliphatic carboxylic acids in good yields and with the formation of the aldehydes in such minimum quantities that recycling thereof is not necessary. More particularly, it is an object of the invention to oxidize propylene to high yields of acrylic acid, with minimum formation of the intermediate aldehyde and hence the elimination of any need for recycling the latter.
• alpha-beta olefins are oxidized to the corresponding unsaturated aliphatic carboxylic acids by reacting the alpha-beta olefin and molecular oxygen in a vapor phase, at temperatures of from 300 C. to 500 C., and in the presence of a catalyst consisting of molybdenum, vanadium, tellurium, oxygen and, in the given case, other elements capable of combining with tellurium to form alloys or tellurides in which there is present at least one of oxygen, molybdenum, and/ or vanadium, and/or tellurium having an oxidation state lower than the maximum.
• a catalyst consisting of molybdenum, vanadium, tellurium, oxygen and, in the given case, other elements capable of combining with tellurium to form alloys or tellurides in which there is present at least one of oxygen, molybdenum, and/ or vanadium, and/or tellurium having an oxidation state lower than the maximum.
• the ratios between the elements constituting the catalyst may vary within a Wide range.
• molybdenum there may be used from 2.0 to 0.05 gram atoms of vanadium and from 2.0 to 0.02 gram atoms of tellurium, preferably from 1.0 to 0.1 gram atom of vanadium and from 1.0 to 0.1 gram atom of tellurium.
• the molybdenum and vanadium are subjected, for example as ammonium salts, to a heat treatment at temperatures comprised between 350 C. and 550 C., in the absence of oxygen.
• the tellurium may be added either before or after the heat treatment.
• the catalyst used in the present process is prepared by evaporating an aqueous solution of ammonium para-molybdate and ammonium meta-vanadate to dryness, and then subjecting the product thus obtained, to a heat treatment at temperatures comprised between 350 C. and 550 C., for a time varying from 2 to 16 hours, and in the absence of oxygen. Tellurium, tellurium dioxide, or a metal telluride, for instance, nickel telluride, is then mixed mechanically with the heat-treated product.
• the catalyst is prepared by evaporating an aqueous solution of ammonium para-molybdate, ammonium meta-vanadate, and telluric acid to dryness and subjecting the product thus obtained to heat treatment at temperatures comprised between 350 C. and 550 C., for from 2 to 16 hours, in the absence of oxygen.
• the oxides of those elements may be used, for instance molybdenum trioxide and vanadium pentaoxide.
• the oxides are mixed together and the mixture is then subjected to a heat treatment in the presence of a gas containing ammonia, and at temperatures comprised between 350 C. and 550 C.
• tellurium metal other products containing the element may be used, such as, for instance, tellurium dioxide, metal tellun'des, telluric acid, and ammonium tellurate.
• the catalyst may be used with or without a carrier. Suitable carriers or supports include silica, alumina, silicaalumina, pumice stone, silicium carbide, etc. Furthermore, the catalyst may be used as a fixed or as a fluidized bed.
• the reaction temperature may vary from 300 C. to 500 C., but is preferably in the range 350 C. to 420 C.
• the reaction may be conducted at atmospheric pressure, or it may be conducted at increased pressure (e.g., up to 10 absolute atms.) in order to increase production of unsaturated acid.
• the contact time defined as the ratio between the apparent volume of the catalyst and the volume of the fed gas under the given reaction conditions in a unit of time, may vary from 0.05 to 25 seconds, but is preferably from 0.5 to 10 seconds.
• the oxygen used to oxidize the alpha-beta olefins may originate from any appropriate source. Air is preferred.
• the oxygen/olefin molar ratio may be from 0.5:1 to 5:1, and is preferably from 1:1 to 3:1.
• the oxidation is preferably conducted in the presence of one ormore diluents, such as: nitrogen, steam, carbon dioxide, and saturated hydrocarbons.
• diluents such as: nitrogen, steam, carbon dioxide, and saturated hydrocarbons.
• steam may be useful for its effectiveness in dissipating the reaction heat, or when the formation of acetic acid is not undesirable. Furthermore, steam permits an increase in the concentration of propylene, restricting the inflammability of the air/propylene mixture.
• the present invention provides a very advantageous process for the preparation of alpha-beta unsaturated aliphatic carboxylic acids, particularly acrylic acid.
• alpha-beta unsaturated aliphatic carboxylic acids particularly acrylic acid.
• Example 1 about 120 Nl/hour of a gas consisting of 10% of ammonia and 90% of nitrogen. At various time intervals, 40 g. samples were taken out and to each sample there was added the same quantity (3.8 g.) of nickel telluride (NiTe The samples were then kneaded, dried, granulated and finally tested on the equipment specified in Example 1.
• NiTe nickel telluride
• the following table shows the results of these tests carried out at a temperature of 370 C., under a pressure of 1.2 absolute atm., with a contact time of 2 seconds and with a feed-mixture consisting of 5% by volume of propylene, 42.5% of air and 52.5% of nitrogen.
• EXAMPLE 1 175.6 g. of ammonium paramolybdate were dissolved in 300 cc. of water. Thereupon there were added 22.8 g. of ammonium metavanadate and the whole was then heated until complete dissolution was attained. This solu tion was evaporated to dryness and the product was reduced into granules and subdivided into three parts: a, b and c, which were activated at the same temperature of 450 C., for the same period of time (8 hours), but in difierent atmospheres, i.e.:
• part a in an air current
• part b in a nitrogen current
• part c in a current of nitrogen containing 10% of NH 50 g. of each activated product were admixed with 4.9 g. of tellurium dioxide, kneaded with a little water, dried and reduced into granules having a diameter comprised between 0.2 and 0.3 mm., thereby originating respectively catalysts A, B and C.
• the catalysts were tested by filling them into a steel reactor 100 mm. long and with an inside diameter of 10 mm., immersed in a bath of molten tin, into which was sent a gaseous mixture consisting of 5% by volume of propylene, 42.5 of air and 52.5% of nitrogen.
• EXAMPLE 3 An aqueous solution containing 55 g. of ammonium paramolybdate, 7.26 g. of ammonium meta-vanadate and 7.14 g. of telluric acid, was evaporated to dryness and subsequently subejected to activation in a nitrogen current at 450 C., for 8 hours. Thereby, a catalyst was obtained which was used in an oxidation test carried out on the same equipment cited in Example 1, using a feedmixture consisting of 5% by volume of propylene, 42.5% of air and 52.5% of nitrogen, at a temperature of 360 C. and under a pressure of 1.2 absolute atm., with a contact time of 2 seconds.
• EXAMPLE 5 45 g. of a product based on molybdenum and vanadium, obtained as described in Example 1 (part b), were soaked with an aqueous solution containing 5.3 g. of telluric acid.
• the product thus obtained was then dried in an oven and additioned with an aqueous solution containing hydrazine in excess for reducing the telluric acid to metaltellurium. Thereupon, the product was again brought to dryness and was then heated up to 300 C. in a nitrogen current in order to eliminate the excess hydrazine. Finally, the product was granulated to particles having a diameter comprised between 0.2 and 0.3 mm. It was then tested under the same reaction conditions as those used in Example 1, except for the temperature which was kept at 370 C. and the contact time which was maintained at 2 seconds. The results of these tests were the following:
• Example 1 To a compound based on molybdenum and vanadium, obtained as described in Example 1 (part b), was added tellurium in the form of molybdenum and cobalt telluride (CoMoTe).
• the recorded data refer to tests carried out with a feed-mixture consisting of 5% by volume of propylene, 55% of air, 40% nitrogen, at a temperature of 360 C., under a pressure of 1.2 absolute atm. and with a contact time of 2 seconds.
• the test equipment was the same as that described in Example 1.
• Example 2 Into a reactor like that described in Example 1, charged with the above granules, was fed a mixture consisting of 5% by volume of propylene, 55% of air and 40% of nitrogen. At a temperature of 360 C., under a pressure of 1.2 absolute atm., and with a contact time of 2 seconds, the following results were obtained:
• EXAMPLE 12 36 g. of ammonium paramolybdate were dissolved in 350 cc. of water. To this solution were then added 48.5 g. of ammonium metavanadate and the mixture was evaporated to dryness under stirring.
• the dry product was activated in a Pyrex glass tube in a nitrogen current, at 450 C. for 8 hours.
• 50 g. of the activated product were additioned with 48.2 g. of NiTe mixed, kneaded with a little water, dried and finally reduced into granules having a diameter comprised between 0.2 and 0.3 mm.
• the tests with this catalyst, conducted as described in Example 11, gave the following results:
• the solution was used to impregnate 81 g. of microspheroidal silica.
• the product thus obtained was dried in an oven at 110 C. and then activated for 8 hours in a current of nitrogen at 450 C.
• the carrier represented 70% by weight of the whole catalyst.
• EXAMPLE 14 47.4 g. of ammonium paramolybdate were dissolved in H O. To this solution were then added 3.1 g. of ammonium metavanadate and the mixture was heated until a solution was obtained, which was then brought up to a volume of 76 cc. This solution was used to impregnate 69.6 g. of microspheroidal silica. The product thus obtained was dried in an oven at 110 C., then activated in an N current at 420 C., for 8 hours; it was again impregnated with an aqueous solution containing 5.16 g. of telluric acid, and finally was dried again at 110 C.
• EXAMPLE 15 A gaseous mixture consisting of 8.4% by volume of propylene, 67.6% of air, and 24% of steam was fed over a catalyst exactly like that described in Example 4.
• EXAMPLE 16 305 g. of a product based on molybdenum and vanadium, prepared and activated as described in Example 1 (part b), were mixed with 147.5 g. of nickel telluride.
• EXAMPLE 17 A test was carried out on a catalyst prepared as described in Example 7, but activated at a temperature of 420 C., using a feed-mixture consisting of 5% by volume of propylene, 55% of air and 40% of nitrogen, at a temperature of 350 C., under a pressure of 1.2 absolute atm., and with a contact time of 3 seconds.
• Example 1 The testing technique was that described in Example 1. During the test, a high percentage of air was used in order to determine whether, with time, the phenomenon of reoxidation of the catalyst with the consequent loss of the starting performance level would occur. However, the results recorded in the following table show how the activity of the catalyst remained constant with time.
• the final solution was used to impregnate 89.7 g. of microspheroidal silica.
• the product thus obtained was dried in an oven at C., activated in a nitrogen current for 8 hours at 450 C., impregnated again with an aqueous solution containing 22.9 g. of telluric acid and, finally, dried again at 110 C.
• a process for preparing acrylic acid characterized in that propylene and molecular oxygen are reacted in vapor phase at a temperature of from 300 C. to 500"v C. and in contact with a catalyst consisting of molybdenum, vanadium, tellurium and oxygen and obtained from molybdenum and vanadium ammonium salts which have been heat-treated in advance, in the absence of oxygen, in a nitrogen gas atmosphere, and at a temperature of from 350 C.
• tellurium compound selected from the group consisting of tellurium dioxide, telluric acid and nickel telluride and cobalt-molybdenum telluride, the vanadium/molybdenum atomic ratio in the catalyst being 0.05 to 2.0, and the tellurium/molybdenum atomic ratio therein being from 0.02 to 2.0.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Catalysts (AREA)
• Transition And Organic Metals Composition Catalysts For Addition Polymerization (AREA)

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Cited By (17)

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• 1969
  • 1969-12-09 SE SE16940/69A patent/SE368777B/xx unknown
  • 1969-12-09 NL NL6918448A patent/NL6918448A/xx unknown
  • 1969-12-10 GB GB60179/69A patent/GB1287483A/en not_active Expired
  • 1969-12-10 FR FR6942728A patent/FR2026214A1/fr not_active Withdrawn
  • 1969-12-12 DE DE19691962431 patent/DE1962431A1/de active Granted
  • 1969-12-12 US US00884734A patent/US3736355A/en not_active Expired - Lifetime
  • 1969-12-15 ES ES374571A patent/ES374571A1/es not_active Expired
  • 1969-12-15 BE BE743146D patent/BE743146A/xx unknown

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