Classifications

• • 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
  • C07C51/255—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of compounds containing six-membered aromatic rings without ring-splitting
  • C07C51/265—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of compounds containing six-membered aromatic rings without ring-splitting having alkyl side chains which are oxidised to carboxyl groups
• • 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
  • B01J23/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
  • B01J23/20—Vanadium, niobium or tantalum
  • B01J23/22—Vanadium
• • 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
  • B01J23/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
  • B01J23/24—Chromium, molybdenum or tungsten
  • B01J23/26—Chromium
• • 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
  • B01J27/14—Phosphorus; Compounds thereof
  • B01J27/16—Phosphorus; Compounds thereof containing oxygen, i.e. acids, anhydrides and their derivates with N, S, B or halogens without carriers or on carriers based on C, Si, Al or Zr; also salts of Si, Al and Zr
  • B01J27/18—Phosphorus; Compounds thereof containing oxygen, i.e. acids, anhydrides and their derivates with N, S, B or halogens without carriers or on carriers based on C, Si, Al or Zr; also salts of Si, Al and Zr with metals other than Al or Zr
• • 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
  • B01J27/14—Phosphorus; Compounds thereof
  • B01J27/186—Phosphorus; Compounds thereof with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
  • B01J27/195—Phosphorus; Compounds thereof with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium with vanadium, niobium or tantalum
  • B01J27/198—Vanadium
• • 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
  • C07C51/31—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation of cyclic compounds with ring-splitting
  • C07C51/313—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation of cyclic compounds with ring-splitting with molecular oxygen

Definitions

• the anhydrides of aromatic polycarboxylic acids have a wide variety of applications, more particularly the manufacture of plasticizers, snythetic resins and fibers.
• the most often used anhydrides are the phthalic and pyromellitic anhydrides.
• These anhydrides may be prepared by vapor-phase oxidation of aromatic hydrocarbons selected from the group consisting of naphthalene, octahydroanthracene and aromatic hydrocarbons having at least two alkyl substituents in ortho position and having the general formula wherein R and R are alkyl radicals which may be straightor branched-chain and which contain from I to 6 carbon atoms and which may be the same or different, R and R are hydrogen or an alkyl radical of from I to 4 carbon atoms and which may be the same or different, the total number of carbon atoms of said alkylaromatic hydrocarbons being no greater than 18.
• the vapor-phase oxidation of these alkylaromatic hydrocarbons generally is carried out in the presence of a catalyst consisting of vanadium oxide or mixtures of vanad um oxide and various promoters, and a refractory carrier such as silica, alumina, mixtures of silica and alumina, silicium carbide and the like.
• a catalyst consisting of vanadium oxide or mixtures of vanad um oxide and various promoters
• a refractory carrier such as silica, alumina, mixtures of silica and alumina, silicium carbide and the like.
• the desired acid anhydride generally is obtained in admixture with relatively large amounts of oxidation by-products.
• the known catalysts in general, do not have satisfactory selectivity.
• the pyromellitic dianhydride or l,2,4,S-benzenetetracarboxylic acid dianhyide obtained contains by-products such as trimellitic acid anhydridc, 4, S-dimethylphthalic acid, and 4- methylphthalic acid anhydride.
• trimellitic acid anhydridc 4, S-dimethylphthalic acid
• 4- methylphthalic acid anhydride 4- methylphthalic acid anhydride.
• An object of the present invention is to provide an improved process for the vapor-phase oxidation of hydrocarbons.
• Another object of the present invention is to provide a new and improved catalyst for the vapor-phase oxidation of aromatic hydrocarbons to the corresponding 2 acid anhydride with minimum formation of by-products.
• a vapor-phase oxidation which comprises carrying out the oxidation of alkyl aromatics having the general formula wherein R and R are alkyl radicals which may be straightor branched-chain and which contain from 1 to 6 carbon atoms and which may be the same or different, R and R are hydrogen or an alkyl radical of from I to 4 carbon atoms and which may be the same or different, the total number of carbon atoms of said alkylaromatic hydrocarbons being no greater than 18 in the presence of a catalyst consisting essentially of a carrier and vanadium oxide which is deposited on the carrier by means of hydrolysis of vanadium oxytrihalide followed by calcination of the catalyst.
• the halide of the vanadium oxytrihalide is one selected from the group consisting of chlorine and bromine, the oxidation temperature being between 300 and 550C.
• the catalyst of the present invention is prepared by impregnating a refractory carrier with a liquid oxytrihalide of vanadium, removing the excess of oxytrihalide, hydrolyzing the oxytrihalide impregnated onto the carrier and calcining the catalyst, the halide being selected from the group consisting of chlorine and bromine.
• the refractory carrier which is used in any usual form, for instance beads, pellets, cylinders, vermicelli and the like, consists of silica, alumina, mixtures of silica and alumina, silicium carbide or any other such refractory material.
• the liquid oxytrihalide of vanadium with which the carrier is impregnated is one prepared by reacting chlorine or bromine with vanadium oxides.
• Vanadium oxytrichloride is preferably used and also may be prepared by reacting thionyl chloride with vanadium pentoxide, according to the reaction V 0 3 SOCl 2 VOCl +,3 S0 During the impregnation of the carrier with vanadium oxytrihalide, it is preferred to avoid the presence of moisture and, consequently, the carrier should be previously dried. According to a preferred embodiment of the present invention, the carrier is immersed into the liquid oxytrihalide of vanadium removed and the excess of oxytrihalide thereafter removed.
• the immersion time depends on a number of considerations, including the nature of the carrier, the size and porosity of the carrier particles. Any other process, however, such as spraying, vapor-phase impregnation or the like, may be used, at atmospheric, superor sub-atmospheric pressure.
• Water, steam or a carrier gas, such as air, which is saturated by water, is used for hydrolyzing the oxytrihalide of vanadium.
• This hydrolysis is carried out at a temperature which may be between 0 and l50C, preferably between about 5 and l00C and more particularly between l0 and 50C.
• the hydrolysis time depends on many factors, such as temperature and flow rate of the hydrolysing gas, particle size of the carrier,
• the hydrolysis is conveniently carried out by using any method allowing an intimate contact between the carrier particles and the hydrolysing agent.
• the amount of vanadium oxide on the catalyst employed in the process of the present invention may be varied within wide limits and depends principally on the particle size and porosity of the carrier. Catalysts with a high content of vanadium oxide may be prepared by carrying out successively, several impregnation and hydrolysis operations, with calcination after each hydrolysis or only after the last hydrolysis. It is preferred that the catalysts contain from 0.1 to 25% by weight, more particularly 1 to by weight, of vanadium oxide based on the weight of the final catalyst.
• the catalysts of this invention may contain, in addition to vanadium oxide, other metallic oxides, such as the oxides of titanium, tin, niobium, germanium, chromium, phosphorus and the like, which act as promoters.
• metallic oxides such as the oxides of titanium, tin, niobium, germanium, chromium, phosphorus and the like, which act as promoters.
• These other metallic oxides may be incorporated into the catalyst of the present invention by treating the catalyst carrier with liquid oxytrihalide of vanadium containing a dissolved halide or any soluble salt of the metal, the oxide of which acts as a promoter.
• the carrier is impregnated with vanadium oxytrichloride containing dissolved therein the chloride of titanium, tin, niobium, germanium, chromium, phosphorus or a mixture of these chlorides.
• vanadium oxytrichloride containing dissolved therein the chloride of titanium, tin, niobium, germanium, chromium, phosphorus or a mixture of these chlorides.
• a catalyst impregnated with vanadium oxide together with one or more of these promotors.
• These promotors also may be incorporated into the catalyst before or after formation of the vanadium oxide.
• the catalyst carrier may be impregnated with a halide or a salt of one of the above mentioned metals or by a mixture of such halides and/or salts which are then converted into the corresponding oxides.
• the carrier containing the promotor(s) is then treated with the vanadium oxytrichloride or vanadium oxytribromide and the product hydrolyzed and calcinated. Additionally, the metallic promotors may be incorporated into the catalyst by using other known methods.
• the amount of the promoter, if any, in the catalyst will depend upon the physical properties of the carrier, on the amount of metal halide or metal salt which is used and on the number of treatments. Catalysts containing up to 25% by weight of promotors may be prepared. However, in general, the promotor content of the catalyst usually will not exceed l0% by weight, these percentages being based on the weight of the final catalyst.
• the present process is useful for the oxidation of such aromatic hydrocarbons as naphthalene, octahydroanthracene and polyalkylbenzenes having at least two alkyl substituents, which may be the same or different, in ortho position.
• polyalkylbenzenes include l,2-dimethylbenzene or ortho-xylene, l-methyl-Z- butyl-benzene, l,2-diisopropylbenzene, 1,2-diethylbenzene, l-methyl-2(4-methylpentyl)benzene, l-methyl-2-isopropylbenzene, l -methyl-2-propylbenzene,
• Anhydrides of the corresponding benzenepolycarboxylic acids namely o-phthalic anhydride and pyromellitic dianhydride, are obtained by oxidizing the above cited hydrocarbons.
• the present vaporphase oxidation process is carried out at temperatures generally, of from 300 to 550C, although temperatures outside these limits may be employed in some circumstances.
• the temperature depends principally on the feed.
• o-xylene is preferably oxidized at a temperature of from 325 to 475C while durene is preferably oxidized at 350-450C.
• Pressure may also be varied, but the oxidation is generally performed at about atmospheric pressure.
• the other operating conditions, such as the relative proportions and rates of flow of the reactants, and other features of the process, are substantially the same as in the processes generally used for oxidizing aromatic hydrocarbons into anhydrides of benzenepolycarboxylic acids.
• a catalyst carrier 400 ml consisting essentially of silicium carbide and containing 25 to 30% of SiO and in the form of beads with an average diameter of 4.7 mm, was calcinated during 1 hour at 350C. There was obtained 372.5 g of catalyst carrier.
• This carrier was introduced into a Pyrex cylindrical reactor (diameter: 79 mm; height: 200 mm) having 3 apertures at the top and 1 aperture at the bottom.
• One of the top apertures was used to introduce vanadium oxytrichloride.
• the other top apertures were respectively used for the removal of the exhaust gases and for the removal of the vapors which were formed during the hydrolysis.
• the bottom aperture was used to remove the excess of VOCl and to introduce the hydrolysis agent.
• the lower part of the reactor contained a bed (depth: 20 mm) of aluminium Raschig-rings. A current of dry and pure nitrogen to remove the moisture was passed over the catalyst carrier in the reactor for 30 minutes.
• VOCl was introduced in an amount (225 ml) such that the carrier was completely immersed by this liquid, at 25C. After 15 minutes, the excess of VOCl was withdrawn, a current of nitrogen being introduced through the top of the reactor to aid in draining the liquid. The VOCl was then hydrolyzed during 1 hour by passing into contact therewith at 25C a stream of air saturated with water, this air being introduced through the bottom of the reactor at a rate of 1200 liters/hour. The catalyst was then removed from the reactor, dried by passing dry air thereover for 16 hours at C and then calcinated during 1 hour at 500C. This catalyst contained 4.9% by weight of vanadium oxide.
• a mixture of durene and air containing 0.2 vol. durene was introduced into a Pyrex reactor containing a fixed bed of 60 ml. of the above prepared catalyst.
• the catalyst in the form of beads, was in admixture with Pyrex beads having the same size as the catalyst beads.
• the oxidation was carried out at 390C and atmospheric pressure, and by using 40 g. of durene per liter of catalyst per hour.
• This run was referred to as Run 1.
• two other similar runs, referred to as Run 2 and Run 3 were carried out under the same conditions but with other catalysts.
• Run 2 employed a catalyst containing 5.3 weight of vanadium oxide prepared by known methods from ammonium meta-vanadate.
• Run 3 employed a catalyst containing 6.8 weight of vanadium oxide prepared by known methods from vanadium oxalate. For each run, the weight yield of crude pyromellitic dianhydride (or solid products ob tained by the oxidation and containing this dianhydride in admixture with other oxidation products) and the purity of the dianhydride (or amounts of dianhydride in this mixture) were determined and were used to calculate the yield of pure dianhydride of pyromellitic acid or PMDA based on the feed.
• Example I The process described in Example I was substantially repeated by oxidizing durene in the presence of a catalyst in the form of beads of silicium carbide containing 4.9% by weight of vanadium oxide and 0.3% by weight of titanium oxide.
• This catalyst was prepared as above described from vanadium oxytrichloride containing dissolved therein titanium tetrachloride.
• the yield of PMDA as a function of the temperature was the follow- Temperature Yield of PMDA (weight 366C 72.5% 380C 97.3% 395C 85.9%
• Example 2 was substantially repeated except that l',2,4-trimethyl-5-isopropylbenzene was the feed. PMDA was obtained with a selectivity higher than 80%.
• EXAMPLE 6 A catalyst prepared as described in Example I and containing 7.1% by weight of vanadium oxide was used for the vapor-phase oxidation of naphthalene at 415C. Phthalic anhydride was obtained with a yield of 76 wt.
• EXAMPLE 4 The vapor-phase oxidation of o-xylene was carried out in the presence of a catalyst substantially the same A catalyst as described in Example I was prepared. However, the catalyst carrier was first impregnated with titanium chloride, hydrolyzed and calcined and thereafter impregnated by vanadium oxytrichloride, hydrolyzed and calcined. The catalyst contained 5.25 wt. of vanadium oxide and 0.94 wt. of titanium oxide. Durene was oxidized with this catalyst as described in Example l, but at a temperature of 380C. PMDA was obtained with a yield of 82.4% by weight.
• said aromatic hydrocarbon is one selected from the group consisting of naphthalene and o-xylene and wherein said temperature is between about 325 and 500C.
• aromatic hydrocarbon is selected from the group consisting of octahydroanthracene and tetramethylbenzene
• said temperature is between about 300 and 500C.
• said metal oxide promotor is an oxide of a metal selected from the group consisting of titanium, tin, niobium, germanium, chromium, phosphorus, and mixtures thereof.
• said catalyst is prepared by the steps consisting essentially of impregnating said refractory carrier with an oxytrihalide of vanadium in which the halide is selected from the group consisting of chlorine and bromine, hydrolyzing said oxytrihalide of vanadium and then calcining said catalyst.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Catalysts (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
• Heterocyclic Carbon Compounds Containing A Hetero Ring Having Oxygen Or Sulfur (AREA)
• Furan Compounds (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=3841909

Family Applications (1)

Country Status (9)

Cited By (6)

Families Citing this family (2)

Citations (5)

• 1973
  • 1973-05-04 BE BE130732A patent/BE799085A/xx unknown
  • 1973-10-26 US US410275A patent/US3925425A/en not_active Expired - Lifetime
• 1974
  • 1974-02-02 ZA ZA00740918A patent/ZA74918B/xx unknown
  • 1974-02-19 CA CA192,979A patent/CA1023373A/en not_active Expired
  • 1974-02-19 NL NL7402243A patent/NL7402243A/xx not_active Application Discontinuation
  • 1974-02-28 GB GB915374A patent/GB1411212A/en not_active Expired
  • 1974-03-09 DE DE2411294A patent/DE2411294A1/de active Pending
  • 1974-03-27 FR FR7410453A patent/FR2228048A1/fr not_active Withdrawn
  • 1974-04-26 JP JP49046706A patent/JPS5013349A/ja active Pending

Patent Citations (5)

Also Published As

Similar Documents