US3331870A - Oxidation of aromatic hydrocarbons - Google Patents
Oxidation of aromatic hydrocarbons Download PDFInfo
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- US3331870A US3331870A US365816A US36581664A US3331870A US 3331870 A US3331870 A US 3331870A US 365816 A US365816 A US 365816A US 36581664 A US36581664 A US 36581664A US 3331870 A US3331870 A US 3331870A
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- United States
- Prior art keywords
- oxidation
- aromatic hydrocarbons
- xylenes
- acid
- oxygen
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- Expired - Lifetime
Links
- 230000003647 oxidation Effects 0.000 title claims description 10
- 238000007254 oxidation reaction Methods 0.000 title claims description 10
- 150000004945 aromatic hydrocarbons Chemical class 0.000 title description 10
- 238000000034 method Methods 0.000 claims description 33
- 239000008096 xylene Substances 0.000 claims description 15
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 11
- 239000001301 oxygen Substances 0.000 claims description 11
- 229910052760 oxygen Inorganic materials 0.000 claims description 11
- -1 HALIDE ANION Chemical class 0.000 claims description 10
- 229910001507 metal halide Inorganic materials 0.000 claims description 10
- 150000005309 metal halides Chemical class 0.000 claims description 10
- 150000003738 xylenes Chemical class 0.000 claims description 9
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 5
- 229910052708 sodium Inorganic materials 0.000 claims description 5
- 239000011734 sodium Substances 0.000 claims description 5
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 4
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims description 4
- 229910052744 lithium Inorganic materials 0.000 claims description 4
- 229910052700 potassium Inorganic materials 0.000 claims description 4
- 239000011591 potassium Substances 0.000 claims description 4
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 3
- 229910052788 barium Inorganic materials 0.000 claims description 3
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 claims description 3
- 229910052791 calcium Inorganic materials 0.000 claims description 3
- 239000011575 calcium Substances 0.000 claims description 3
- XMBWDFGMSWQBCA-UHFFFAOYSA-N hydrogen iodide Chemical compound I XMBWDFGMSWQBCA-UHFFFAOYSA-N 0.000 claims description 3
- CPELXLSAUQHCOX-UHFFFAOYSA-M Bromide Chemical compound [Br-] CPELXLSAUQHCOX-UHFFFAOYSA-M 0.000 claims description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 2
- 229910052782 aluminium Inorganic materials 0.000 claims description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 2
- 229910052749 magnesium Inorganic materials 0.000 claims description 2
- 239000011777 magnesium Substances 0.000 claims description 2
- 150000003022 phthalic acids Chemical class 0.000 claims description 2
- KKEYFWRCBNTPAC-UHFFFAOYSA-N benzene-dicarboxylic acid Natural products OC(=O)C1=CC=C(C(O)=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-N 0.000 description 13
- XNGIFLGASWRNHJ-UHFFFAOYSA-N phthalic acid Chemical compound OC(=O)C1=CC=CC=C1C(O)=O XNGIFLGASWRNHJ-UHFFFAOYSA-N 0.000 description 11
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 8
- 239000002253 acid Substances 0.000 description 8
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 description 6
- 150000007513 acids Chemical class 0.000 description 6
- 239000002585 base Substances 0.000 description 6
- 239000003054 catalyst Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- YNQLUTRBYVCPMQ-UHFFFAOYSA-N Ethylbenzene Chemical compound CCC1=CC=CC=C1 YNQLUTRBYVCPMQ-UHFFFAOYSA-N 0.000 description 4
- URLKBWYHVLBVBO-UHFFFAOYSA-N Para-Xylene Chemical group CC1=CC=C(C)C=C1 URLKBWYHVLBVBO-UHFFFAOYSA-N 0.000 description 4
- WPYMKLBDIGXBTP-UHFFFAOYSA-N benzoic acid Chemical compound OC(=O)C1=CC=CC=C1 WPYMKLBDIGXBTP-UHFFFAOYSA-N 0.000 description 4
- 150000001735 carboxylic acids Chemical class 0.000 description 4
- 229930195733 hydrocarbon Natural products 0.000 description 4
- 150000002430 hydrocarbons Chemical class 0.000 description 4
- 150000004996 alkyl benzenes Chemical class 0.000 description 3
- 150000007514 bases Chemical class 0.000 description 3
- ZCDOYSPFYFSLEW-UHFFFAOYSA-N chromate(2-) Chemical compound [O-][Cr]([O-])(=O)=O ZCDOYSPFYFSLEW-UHFFFAOYSA-N 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 235000011121 sodium hydroxide Nutrition 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- QPUYECUOLPXSFR-UHFFFAOYSA-N 1-methylnaphthalene Chemical compound C1=CC=C2C(C)=CC=CC2=C1 QPUYECUOLPXSFR-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 239000005711 Benzoic acid Substances 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 2
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 241001647090 Ponca Species 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 229910000288 alkali metal carbonate Inorganic materials 0.000 description 2
- 150000008041 alkali metal carbonates Chemical class 0.000 description 2
- 125000000217 alkyl group Chemical group 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 235000010233 benzoic acid Nutrition 0.000 description 2
- 229910052792 caesium Inorganic materials 0.000 description 2
- TVFDJXOCXUVLDH-UHFFFAOYSA-N caesium atom Chemical compound [Cs] TVFDJXOCXUVLDH-UHFFFAOYSA-N 0.000 description 2
- 125000004432 carbon atom Chemical group C* 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000000460 chlorine Substances 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 150000004679 hydroxides Chemical class 0.000 description 2
- QQVIHTHCMHWDBS-UHFFFAOYSA-N isophthalic acid Chemical compound OC(=O)C1=CC=CC(C(O)=O)=C1 QQVIHTHCMHWDBS-UHFFFAOYSA-N 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- ZWLPBLYKEWSWPD-UHFFFAOYSA-N o-toluic acid Chemical compound CC1=CC=CC=C1C(O)=O ZWLPBLYKEWSWPD-UHFFFAOYSA-N 0.000 description 2
- 239000007800 oxidant agent Substances 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- 125000005575 polycyclic aromatic hydrocarbon group Chemical class 0.000 description 2
- 229910052701 rubidium Inorganic materials 0.000 description 2
- IGLNJRXAVVLDKE-UHFFFAOYSA-N rubidium atom Chemical compound [Rb] IGLNJRXAVVLDKE-UHFFFAOYSA-N 0.000 description 2
- JHJLBTNAGRQEKS-UHFFFAOYSA-M sodium bromide Chemical compound [Na+].[Br-] JHJLBTNAGRQEKS-UHFFFAOYSA-M 0.000 description 2
- 229910052725 zinc Inorganic materials 0.000 description 2
- 239000011701 zinc Substances 0.000 description 2
- VIDOPANCAUPXNH-UHFFFAOYSA-N 1,2,3-triethylbenzene Chemical class CCC1=CC=CC(CC)=C1CC VIDOPANCAUPXNH-UHFFFAOYSA-N 0.000 description 1
- PLHMRFZIONHMNF-UHFFFAOYSA-N 1,2,3-triethylnaphthalene Chemical class C1=CC=C2C(CC)=C(CC)C(CC)=CC2=C1 PLHMRFZIONHMNF-UHFFFAOYSA-N 0.000 description 1
- RQHPYGROUIBUSW-UHFFFAOYSA-N 1,2,3-trimethylnaphthalene Chemical class C1=CC=C2C(C)=C(C)C(C)=CC2=C1 RQHPYGROUIBUSW-UHFFFAOYSA-N 0.000 description 1
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- WKBOTKDWSSQWDR-UHFFFAOYSA-N Bromine atom Chemical compound [Br] WKBOTKDWSSQWDR-UHFFFAOYSA-N 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000008044 alkali metal hydroxides Chemical class 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 239000000908 ammonium hydroxide Substances 0.000 description 1
- 150000001454 anthracenes Chemical class 0.000 description 1
- 238000010923 batch production Methods 0.000 description 1
- GDTBXPJZTBHREO-UHFFFAOYSA-N bromine Substances BrBr GDTBXPJZTBHREO-UHFFFAOYSA-N 0.000 description 1
- 229910052794 bromium Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 239000003518 caustics Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 150000001846 chrysenes Chemical class 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 150000005195 diethylbenzenes Chemical class 0.000 description 1
- 229910001882 dioxygen Inorganic materials 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 150000002220 fluorenes Chemical class 0.000 description 1
- 150000002469 indenes Chemical class 0.000 description 1
- 150000007529 inorganic bases Chemical class 0.000 description 1
- PNDPGZBMCMUPRI-UHFFFAOYSA-N iodine Chemical compound II PNDPGZBMCMUPRI-UHFFFAOYSA-N 0.000 description 1
- 150000002790 naphthalenes Chemical class 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000020477 pH reduction Effects 0.000 description 1
- 150000002987 phenanthrenes Chemical class 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- XMXNVYPJWBTAHN-UHFFFAOYSA-N potassium chromate Chemical class [K+].[K+].[O-][Cr]([O-])(=O)=O XMXNVYPJWBTAHN-UHFFFAOYSA-N 0.000 description 1
- 239000012286 potassium permanganate Substances 0.000 description 1
- 150000003220 pyrenes Chemical class 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 239000011541 reaction mixture Substances 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 229910052712 strontium Inorganic materials 0.000 description 1
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 description 1
- 239000012209 synthetic fiber Substances 0.000 description 1
- 229920002994 synthetic fiber Polymers 0.000 description 1
- 150000003518 tetracenes Chemical class 0.000 description 1
- 150000005199 trimethylbenzenes Chemical class 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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
Definitions
- This invention rel-ates to the oxidation of aromatic hydrocarbons to carboxylic acids. More particularly, it relates to the oxidation of alkyl-substituted aromatic hydrocarbons to the corresponding carboxylic acids by means of molecular oxygen in the presence of a catalyst.
- the present invention provides a catalytic process for the oxidation of alkyl-substituted aromatic hydrocarbons to the corresponding carboxylic acids, which comprises intimately contacting said alkyl-substituted' aromatic hydrocarbons with a gas containing free oxygen at superatmospheric pressures and elevated temperatures in the presence of aqueous base and a novel catalyst comprising a metal halide.
- Suitable alkyl-substituted aromatic hydrocarbons for use in our process include alkyl-substituted benzenes and alkyl-substituted polycyclic aromatic hydrocarbons.
- suitable polycyclic aromatic hydrocarbons are the alkyl-substituted naphthalenes, anthracenes, phenanthrenes, naphthacenes, chrysenes, pyrenes, indenes, and fluorenes.
- alkyl-substituted aromatic hydrocarbons for use in our process are the alkylbenzenes and alkylnaphthalenes having one to three alkyl groups con- ICC taining from one to three carbon atoms in each group.
- alkylbenzenes and alkylnaphthalenes having one to three alkyl groups con- ICC taining from one to three carbon atoms in each group.
- Examples of preferred materials are the following:
- xylenes are especially preferred.
- the term xylene or xylenes refers to the meta, ortho, and para isomers, and mixtures thereof. In addition, it refers to commercial xylene which is a mixture of the three isomers with a minor amount of ethylbenzene being present.
- phthalic acid refers to any of the isomers of benzenedicarboxylic acid, which are known commonly as phthalic acid, isophthalic acid, and terephthalic acid. Where ethylbenzene is present in the material being oxidized, the product will contain benzoic acid.
- Pressures wthin the range of 375 to 2500 p.s.i.g. and temperatures within the range of 225 to 325 C. can be used in our process.
- any inorganic base or inorganic basic compound can be used in our process provided it has some degree of solubility, even though slight, in water.
- suitable aqueous bases include aqueous solutions of hydroxides of the following metals: lithium, sodium, potassium, rubidium, cesium, calcium, strontium, barium, and zinc.
- suitable basic compounds include carbonates of the following metals: lithium, sodium, potassium, rubidium, cesium, and zinc.
- ammonium hydroxide is suitable for use in our process.
- the preferred bases and basic compounds are the alkali metal hydroxides and alkali metal carbonates which should be in an aqueous solution.
- the total amount and concentration can be varied within wide limits, with the only requirement being that the reaction mixture must be non-acidic at all times. Stated in another way, the amount of aqueous base must be suflicient to provide that the eflluent from the reactor is in the neutral or alkaline range.
- a suitable pH range for the efiluent from the reactor is from about 6 to about 10, with a preferable range being from about 7 to about 8.
- air or a mixture of oxygen and nitrogen can be used as a source for the oxygen used in the process. Again, this does not form a salient feature of our invention.
- the metal halides which are suitable for our process, maybe characterized as follows: (a) the halide ion can be chlorine, bromine, or iodine, and (b) the metal can be lithium, sodium, potassium, magnesium, calcium, barium, or aluminum.
- the amount of metal halide which can be used varies from 0.001 to 0.50 part per part of hydrocarbon used. Preferably, we use from 0.01 to 0.14 part of metal halide per part of hydrocarbon.
- acids produced by our process can be used to prepare polyesters, plasticizers, and synthetic fibers.
- Prcedure A stirred, nickel autoclave was charged with the xylene and aqueous caustic, sealed, and heated to 240 C.
- a known amount of metal halide was added to the reactants.
- Oxygen was admitted at a rate such as to keep the oxygen partial pressure at the desired value. The duration of the run was one hour.
- the product was removed from the autoclave. The unreacted xylene was recovered, and the acids were isolated by acidification, filtering, and drying. The CO was caught in an Ascarite trap.
- Example II shows no significant improvement in yield of total acids but a substan tial improvement in the yield of terephthalic acid.
- Examples IV, VI, VII, and VIII show improvement in both yield of total acids and yield of terephthalic acid.
- Example V shows a substantial increase in yield of total acids with a decrease in percentage yield of terephthalic acid. It should be noted that the net yield. of terephthalic acid in Example V is about twice that of Example III. From the data of these examples, it is readily apparent that the use of a metal halide gives a substantial improvement in the yield of terephthalic acid.
- a process for the oxidation of xylenes, to the corresponding phthalic acids comprising contacting said xylenes with a gas containing free oxygen under a pressure of about 375 to 2500 p.s.i.g. and a temperature of about 225 to 325 C. in the presence of an aqueous base and a metal halide wherein the halide anion .is
- chloride selected from the group consisting of chloride, iodide and present in an amount in the range of 0.01 to 0.14 part Y per part of xylenes.
- aqueous base References Cited is selected from the group consisting of alkali metal UNITED STATES PATENTS hydroxides and alkali metal carbonates.
- halide anion is 2907792 10/1959 McIntyre 260 524 ch1oride 5 FOREIGN PATENTS 8.
- halide anion is 808,581 2/1959 Great Britain. iodide.
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- Organic Chemistry (AREA)
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- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Description
United States Patent OXIDATION OF AROMATIC HYDROCARBONS George C. Feighner and Russell G. Rose, Ponca City,
Okla., and Paul A. Lobo, Scheveningen, Netherlands,
assignors to Continental Oil Company, Ponca City,
Okla, a corporation of Delaware No Drawing. Filed May 7, 1964, Ser. No. 365,816
9 Claims. (Cl. 260-524) The present application is a continuation-in-part of application Ser. No. 106,529, filed May 1, 1961 and now abandoned.
This invention rel-ates to the oxidation of aromatic hydrocarbons to carboxylic acids. More particularly, it relates to the oxidation of alkyl-substituted aromatic hydrocarbons to the corresponding carboxylic acids by means of molecular oxygen in the presence of a catalyst.
Numerous methods have been suggested in the prior art as possible methods for the oxidation of such hydrocarbons. All, however, possess certain disadvantages. Only a few methods possess features which render them commercially feasible. Many of the proposed methods employ chemical oxidizing reagents, such as nitric acid, sodium or potassium chromates or dichromates, potassium permanganate, and others. Obviously, methods utilizing chemical oxidizing agents for the oxidation of such hydrocarbons are expensive because of the chemicals consumed. Other methods have employed oxygen or air as the oxidizing agent. Such methods usually employ an oxygen carrier. An example of such a method is US. Patent 2,120,672, issued June 14, 1938, to J. -R. Mares, which teaches a process for the production of benzoic acid by oxidizing aromatic hydrocarbons in the presence of caustic soda and an alkali chromate as an oxygen carrier.
It is, therefore, a principal object of our invention to provide an efiicient process for the oxidation of alkylsubstituted aromatic hydrocarbons to the corresponding carboxylic acids, which process obviates the disadvantages of the prior art. Other objects and advantages of the present invention will be apparent to those skilled in the art as the invention is more fully described.
Broadly stated, the present invention provides a catalytic process for the oxidation of alkyl-substituted aromatic hydrocarbons to the corresponding carboxylic acids, which comprises intimately contacting said alkyl-substituted' aromatic hydrocarbons with a gas containing free oxygen at superatmospheric pressures and elevated temperatures in the presence of aqueous base and a novel catalyst comprising a metal halide.
Having stated the nature of our invention, it may be well to indicate wherein our invention possesses advantages as compared to the process taught by US. Patent No. 2,120,672. The metal halides used in our process are Water-soluble and cause no handling problems, as do the chromates. In addition, the metal halides are relatively inexpensive, as compared to the alkali chromates.
Before proceeding with specific examples illustrating our invention, it might be better, first, to define the materials used and the more important operating conditions of our invention.
Suitable alkyl-substituted aromatic hydrocarbons for use in our process include alkyl-substituted benzenes and alkyl-substituted polycyclic aromatic hydrocarbons. Examples of suitable polycyclic aromatic hydrocarbons are the alkyl-substituted naphthalenes, anthracenes, phenanthrenes, naphthacenes, chrysenes, pyrenes, indenes, and fluorenes. Preferred alkyl-substituted aromatic hydrocarbons for use in our process are the alkylbenzenes and alkylnaphthalenes having one to three alkyl groups con- ICC taining from one to three carbon atoms in each group. Examples of preferred materials are the following:
Toluene Dimethylnaphthalenes Xylenes Trimethylnaphthalenes Trimethylbenzenes Ethylnaphthalene Ethylbenzene Diethylnaphthalenes Diethylbenzenes Triethylnaphthalenes Triethylbenzenes Propylnaphthalene Propylbenzene Isipropylnaphthalene Cumene Dipropylnaphthalenes Dipropylbenzenes Diisopropylnaphthalenes Tripropylbenzenes Tripropylnaphthalenes Triisopropylbenzenes Triisopropylnaphthalenes Methylnaphthalene Particularly preferred materials are the alkylbenzenes having one or two alkyl groups containing from one to three carbon atoms in each group. Of the particularly preferred materials, the xylenes are especially preferred. The term xylene or xylenes refers to the meta, ortho, and para isomers, and mixtures thereof. In addition, it refers to commercial xylene which is a mixture of the three isomers with a minor amount of ethylbenzene being present.
It should be noted that, under the conditions of our invention, complete conversion of xylene to the corresponding phthalic acid does not occur, there being some toluic acid present. Any attempt to convert completely to the phthalic acid results in the production of abnormal amounts of carbon dioxide. Consequently, we have found that it is better to operate under milder conditions and to recycle the unreacted xylene and toluic acid. It should be emphasized, however, that our invention gives an improvement in yield of phthalic acid and reduces the amount of material which must be recycled. The term phthalic acid refers to any of the isomers of benzenedicarboxylic acid, which are known commonly as phthalic acid, isophthalic acid, and terephthalic acid. Where ethylbenzene is present in the material being oxidized, the product will contain benzoic acid.
Pressures wthin the range of 375 to 2500 p.s.i.g. and temperatures within the range of 225 to 325 C. can be used in our process.
Any inorganic base or inorganic basic compound can be used in our process provided it has some degree of solubility, even though slight, in water. Examples of suitable aqueous bases include aqueous solutions of hydroxides of the following metals: lithium, sodium, potassium, rubidium, cesium, calcium, strontium, barium, and zinc. Examples of suitable basic compounds include carbonates of the following metals: lithium, sodium, potassium, rubidium, cesium, and zinc. In addition to the preceding, ammonium hydroxide is suitable for use in our process. The preferred bases and basic compounds are the alkali metal hydroxides and alkali metal carbonates which should be in an aqueous solution.
The total amount and concentration can be varied within wide limits, with the only requirement being that the reaction mixture must be non-acidic at all times. Stated in another way, the amount of aqueous base must be suflicient to provide that the eflluent from the reactor is in the neutral or alkaline range. A suitable pH range for the efiluent from the reactor is from about 6 to about 10, with a preferable range being from about 7 to about 8. These operating conditions are not related to the salient features of 'our invention. Our invention will show an improvement within any of the ranges of operating conditions hereinbefore noted.
Commercially available pure oxygen is the preferred source of oxygen for use in our process. Alternatively, if
O desired, air or a mixture of oxygen and nitrogen can be used as a source for the oxygen used in the process. Again, this does not form a salient feature of our invention.
The metal halides, which are suitable for our process, maybe characterized as follows: (a) the halide ion can be chlorine, bromine, or iodine, and (b) the metal can be lithium, sodium, potassium, magnesium, calcium, barium, or aluminum. The amount of metal halide which can be used varies from 0.001 to 0.50 part per part of hydrocarbon used. Preferably, we use from 0.01 to 0.14 part of metal halide per part of hydrocarbon.
It will be readily apparent to those skilled in the art that many uses exist for the acids produced by our process. For example, they can be used to prepare polyesters, plasticizers, and synthetic fibers.
In order to disclose more clearly the nature of the present invention and the advantages thereof, reference will hereinafter be made to certain specific embodiments which illustrate the flexibility of the herein-described process. It should be clearly understood, however, that this is done solely by way of example and is not to be construed as a limitation upon the spirit and scope of the appended claims.
' Examples I-VIII The following conditions were constant in these examples:
Charge: 66.8 grams p-xylene; 320 grams of 25% NaOH solution (aqueous) Time: 1 hour The conditions which were varied are shown in Table I.
Prcedure.A stirred, nickel autoclave was charged with the xylene and aqueous caustic, sealed, and heated to 240 C. In Examples II and IV-VIII a known amount of metal halide was added to the reactants. Oxygen was admitted at a rate such as to keep the oxygen partial pressure at the desired value. The duration of the run was one hour. After cooling and releasing the pressure, the product was removed from the autoclave. The unreacted xylene was recovered, and the acids were isolated by acidification, filtering, and drying. The CO was caught in an Ascarite trap.
The data on the products obtained are shown in Table Example II, as compared to Example I, shows no significant improvement in yield of total acids but a substan tial improvement in the yield of terephthalic acid. Examples IV, VI, VII, and VIII, as compared to Example 111, show improvement in both yield of total acids and yield of terephthalic acid. Example V, as compared to Example III, shows a substantial increase in yield of total acids with a decrease in percentage yield of terephthalic acid. It should be noted that the net yield. of terephthalic acid in Example V is about twice that of Example III. From the data of these examples, it is readily apparent that the use of a metal halide gives a substantial improvement in the yield of terephthalic acid.
While the examples'given have dealt only with batch operation, our invention is not limited thereto. The process of our invention will work in a continuous process as well as in a batch process.
While particular embodiments of the invention have been described, it will be understood, of course, that the invention is not limited thereto, since many modifications may be made; and it is, therefore, contemplated to cover by the appended claims any such modifications as fall within the true spirit and scope of the invention.
The invention having thus been described, what is claimed and desired to be secured by Letters Patent is:
1. A process for the oxidation of xylenes, to the corresponding phthalic acids, said process comprising contacting said xylenes with a gas containing free oxygen under a pressure of about 375 to 2500 p.s.i.g. and a temperature of about 225 to 325 C. in the presence of an aqueous base and a metal halide wherein the halide anion .is
selected from the group consisting of chloride, iodide and present in an amount in the range of 0.01 to 0.14 part Y per part of xylenes.
TABLE I.REACTION CONDITIONS-EXAMPLES I-VIII Example Weight of Catalyst/ Tempera- Total Partial No. Catalyst Catalyst, g. p-Xylene ture, 0. Pressure, Pressure Ratio p.s.i.g. O2, p.s.i.g.
T Nnne 240 665 II NaBr- 0.9 O. 013 240 700 None 275 1, 125 125 NaCl 9.0 0. 275 1,140 7 150 NaI 0.9 0. 013 275 1, 130 NaBr 0.9 0.013 275 1, 110 170 OaClg 0. 9 0.013 275 1, 120 VIII AlCl;- 0. 9 0. 013 275 l, 130
TABLE II.PRODUCT YIELD AND ANALYSISEXAMPLE I-VIII Analysis of Acids Example CO2, Acid, Terephthalic No. Catalyst Grams Grams Acid, Grams Terephthalic, pTolu1c,
Percent Percent 1. 1 11. 1 30. 1 69. 9 3. 34 2. 3 1l. 6 47. 6 '52. 4 5. 52 11. 4 25. 8 59.6 40. 4 15.38 12. 8 46. 0 64. 3 35. 7 29. 58 9. 7. 57.1 54. 6 45. 4 31.18 10. 7 33.0 65. 3 34. 7 21. 55 12. 0 84. 5 62. 8 37. 2 21. 67 VIII A1013- 11.3 37. 8 61. 2 38. 8 23.13
6. The process of claim 5 wherein the aqueous base References Cited is selected from the group consisting of alkali metal UNITED STATES PATENTS hydroxides and alkali metal carbonates.
7. The process of claim 6 wherein the halide anion is 2907792 10/1959 McIntyre 260 524 ch1oride 5 FOREIGN PATENTS 8. The process of claim 6 wherein the halide anion is 808,581 2/1959 Great Britain. iodide.
9. The process of claim 6 wherein the halide anion LORRAINE WEINBERGER Primary Examineris bromide. SIDNEY B. WILLIAMS, IR., Assistant Examiner.
Claims (1)
1. A PROCESS FOR THE OXIDATION OF XYLENES, TO THE CORRESPONDING PHTHALIC ACIDS, SAID PROCESS COMPRISING CONTACTING SAID XYLENES WITH A GAS CONTAINING FREE OXYGEN UNDER A PRESSURE OF ABOUT 375 TO 2500 P.S.I.G. AND A TEMPERATURE OF ABOUT 225 TO 325* C. IN THE PRESENCE OF AN AQUEOUS BASE AND A METAL HALIDE WHEREIN THE HALIDE ANION IS SELECTED FROM THE GROUP CONSISTING OF CHLORIDE, IODIDE AND BROMIDE AND THE CATION IS SELECTED FROM THE GROUP CONSISTING OF LITHIUM, SODIUM, POTASSIUM, MAGNESIUM, CALCIUM, BARIUM, AND ALUMINUM, SAID METAL HALIDE BEING PRESENT IN AN AMOUNT IN THE RANGE OF 0.002 TO 0.50 PART PER PART OF XYLENES.
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US365816A US3331870A (en) | 1961-05-01 | 1964-05-07 | Oxidation of aromatic hydrocarbons |
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Citations (2)
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GB808581A (en) * | 1955-06-27 | 1959-02-04 | Continental Oil Co | Improvements in or relating to process for the production of carboxylic acids |
US2907792A (en) * | 1955-08-24 | 1959-10-06 | Ici Ltd | Oxidation of organic substances |
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GB808581A (en) * | 1955-06-27 | 1959-02-04 | Continental Oil Co | Improvements in or relating to process for the production of carboxylic acids |
US2907792A (en) * | 1955-08-24 | 1959-10-06 | Ici Ltd | Oxidation of organic substances |
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