Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C49/00—Ketones; Ketenes; Dimeric ketenes; Ketonic chelates
  • C07C49/587—Unsaturated compounds containing a keto groups being part of a ring
  • C07C49/657—Unsaturated compounds containing a keto groups being part of a ring containing six-membered aromatic rings
  • C07C49/665—Unsaturated compounds containing a keto groups being part of a ring containing six-membered aromatic rings a keto group being part of a condensed ring system
  • C07C49/675—Unsaturated compounds containing a keto groups being part of a ring containing six-membered aromatic rings a keto group being part of a condensed ring system having three rings

Definitions

• This invention relates to a simple, highly selective process for the oxidation of fluorenes to corresponding fluorenones
• Fluorenones, particularly 9-fluorenone, are valuable intermediates for the preparation of intermediates for making condensation polymers, such as
• Niznik U S Patent 3,875,2307 has proposed preparing fluorenone from fluorene by oxidation with molecular oxygen in dimethylsulfoxide, using a small amount of an alkali metal hydroxide, at temperatures from ambient to 100°C Hiiro et al (JP Kokai 79/ 144,348, Chem Abs 92 215069q) have proposed oxidizing aromatic or heterocyclic methylene compounds, including diphenylmethane, anthracene and fluorene, in the presence of alkali in 1 ,3-d ⁇ methyl ⁇ m ⁇ dazol ⁇ d ⁇ none
• This invention relates to aprocess for the oxidation of a fluorene compound to a corresponding fluorenone by treating the fluorene compound with an oxidizing gas in the presence of a solid alkali metal or alkaline earth metal oxide or hydroxide or a concentrated aqueous solution thereof in a reaction mixture in a heterocyclic nitrogenous solvent, wherein the reaction mixture is free of a phase-transfer agent, for a time sufficient and at a temperature sufficient to convert the fluorene compound to the fluorenone compound
• each of Ri-R ⁇ is independently selected from hydrogen or substituents which are inert under the reaction conditions employed
• the substituents can advantageously include hydrocarbyl, hydrocarbyloxy, nitro, ammo, substituted ammo, cyano, formyl, keto, hydroxy, carboxy, carboxyalkyl, alkyloxycarbonyl or halogen
• Hydrocarbyl includes alkyl, cycloalkyl, aryl, arylalkylene (aralk), alkylcycloaliphatic and alkylenecycloalkyl, that is, functions containing carbon and hydrogen atoms
• Hydrocarbyl functions include both saturated and unsaturated substituents
• Aryl includes mono- and polycyclic aromatic substituents, for example, phenyl, biphenyl, biaryl, naphthyl, phenanthrenyl, anthracenyl or other aryl groups, including those connected to a fluorene ring structure by an alkylene group
• Alkyl groups include both straight- and branched-chain isomers of methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, t ⁇ decyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, nonadecyl and eicosyl groups, as well as the corresponding unsaturated (alkenyl or alkynyl) groups and higher homologues
• the alkyl groups are of 1 to 20 carbon atoms, more preferably of 1 to 5 carbon atoms, most preferably those of 1 to 3 carbon atoms
• Alkyl of 1 to 5 carbon atoms includes the various methyl, ethyl, propyl, butyl and pentyl isomers Alkyl, aryl, alkaryl
• inert substituents include, but are not limited to alkoxy, aryloxy or alkaryloxy, wherein alkoxy includes methoxy, ethoxy, propyloxy, butoxy, pentoxy, hexoxy, heptoxy, octyloxy, nonyloxy, decyloxy and polyoxyethylene, as well as higher homologues, aryloxy, phenoxy, biphenoxy, or naphthyloxy, and alkaryloxy includes alkyl, alkenyl and alkynyl-substituted aryl
• the fluorene starting material is fluorene itself, that is, a compound of the general formula in which each of Ri-R ⁇ is H
• the process of this invention has been found to be particularly advantageous for the selective oxidation of fluorene in a material, identified as 'crude fluorene concentrate," which contains 45 to 65 percent of fluorene, along with dimethylbiphenyl, t ⁇ methylbiphenyl, acenaphthene, methylacenaphthene and t ⁇ methylnaphthalenes
• a representative fluorene concentrate contains 57 to 60 percent of fluorene and is a clear solid, melting about 60°C This material is advantageously stored in a tank, heated to about 80°C, and pumped to a mixer or reactor
• the process of this invention includes a process of (a) using as a starting material a crude fluorene (having less than about 80 weight percent fluorene with
• the oxidations are carried out in a reaction mixture containing a heterocyclic nitrogenous solvent, for example, pyridine, the lutidines, the picolmes and diazmes, for example, pyrazine or py ⁇ dazme
• a heterocyclic nitrogenous solvent for example, pyridine, the lutidines, the picolmes and diazmes, for example, pyrazine or py ⁇ dazme
• a heterocyclic nitrogenous solvent for example, pyridine, 2,3-lut ⁇ d ⁇ ne, 3-p ⁇ col ⁇ ne, 4-p ⁇ col ⁇ ne, pyrazine and py ⁇ dazine
• the solvents are free of functionality such as carbonyl or hydroxy It is preferred to carry out the process of this invention in heterocyclic nitrogenous solvents, which have a water solubility above about 20 g/ 100 mL at 25°C
• Preferred solvents for the practice of this invention will conveniently be selected from pyridine, the picolines and the lutidines, including alkylamino derivatives thereof Most preferably, the process is done using pyridine
• the process of this invention is carried out in the substantial absence of organic solvents, other than the above-disclosed heterocyclic nitrogenous solvent or solvents
• Substantial absence refers to absence except for inadvertent impurities which may be solvents, particularly impurities such as hydrocarbons in crude fluorene starting materials
• the process is carried out using weight ratios of fluorene compound to heterocyclic nitrogenous solvent from 3 1 to 1 100
• the minimum amount of heterocyclic solvent, usable in the process of this invention, is determined by the solubility of the fluorene compound in the solvent If a solution of fluorene is to be used, the minimum amount of solvent is that in which the fluorene compound forms a saturated solution In some cases, it may be advantageous to use a suspension/slurry of fluorene in the heterogeneous nitrogenous solvent
• the solubility of fluorene in pyridine is about 25 percent by weight at about 25°C
• weight ratios from 3 1 to 1 25 are employed, most preferably from 1 3 to 1 15
• reaction mixtures can contain inert materials, which are normally hydrocarbonaceous
• crude fluorene concentrate contains aromatic hydrocarbons, which are not oxidized under the reaction conditions employed
• hydrocarbon diluents for example, toluene or diphenylmethane
• the solvents used can be commercial grade materials Neither extreme caution in handling the solvents nor extensive purification of the solvents is required
• Alkali metal as used in the specification and claims, includes lithium, sodium and potassium
• Alkaline earth metal as used in the specification and claims, includes magnesium, calcium and barium
• the carbonates can also be used in the practice of this invention, alone or admixed with the oxide or hydroxides
• the alkali metal or alkaline earth metal oxide or hydroxide, or mixture thereof can advantageously be used in solid form, for example, powders or pellets Highly soluble compounds are preferably used in concentrated aqueous solutions, containing a maximum of 50 percent to 75 percent by weight of water When an aqueous solution is used, it is preferred to use a highly concentrated (above about 40 percent by weight of solute) or saturated solution Saturated solutions of sodium hydroxide or potassium hydroxide contain about 50 percent of water, depending upon the temperature Such solutions are conveniently used in the process of the invention It is particularly advantageous, in using concentrated aqueous solutions, particularly of sodium or potassium hydroxide, to use ratios of sodium or potassium hydroxide solution to heterocyclic nitrogenous solvent such that two liquid phases are present in the reaction Such ratios are readily determined by routine experimentation Solid forms of the alkali metal or alkaline earth metal oxides or hydroxides generally contain some water Potassium hydroxide pellets normally contain about 15 percent by weight of water Sodium hydroxide pellets commonly contain about 2 percent by
• the alkali metal or alkaline earth metal oxide or hydroxide is not consumed during the process Therefore, it is feasible in some instances to recycle the oxide or hydroxide in successive runs, whether batch or continuous Recycling the oxide or hydroxide is particularly advantageous when the reaction mixture separates into two phases and the aqueous layer, containing hydroxide solution can be removed and recycled, at least until the solution becomes diluted with excessive amounts of by-product water When diluted, the concentration of hydroxide is optionally adjusted by addition of solid or more concentrated hydroxide solution, and the solution is suitable for use yet again
• the process of the invention is operable over a wide range of water concentrations
• the pyridine phase be stirred with an aqueous solution of base
• the oxidations have also been carried out successfully at water concentrations of about 300 ppm and are feasible at even lower water levels
• the water can be introduced into the reaction mixture by the alkali metal or alkaline earth metal oxide or hydroxide, by the heterocyclic nitrogenous solvent and/or by the fluorene compound being oxidized
• water is a by-product of the reaction
• the oxidizing gas is selected from oxygen or air or mixtures thereof. It is preferred to use oxygen or air/oxygen mixtures in the practice of this invention. Oxygen or air is optionally admixed with inert (non-oxidizing) gases such as nitrogen.
• the process of this invention can be carried out under ambient pressure (about 1 bar (100 kPa)) or under elevated pressures.
• the process is carried out using oxygen as the oxidizing gas, under pressures from 1 bar (100 kPa) to 10 bars (1000 kPa).
• air is alternatively preferably used at these pressures.
• the process of this invention is carried out at moderate temperatures, advantageously from 0°C to 75°C. Preferably, the process is carried out from 10°C to 65°C. 0 Depending upon the conditions selected, quantitative conversion of fluorene compounds to corresponding fluorenones is accomplished rapidly, within reaction times of 1 to 6 hours in batch mode processes.
• Oxygen consumption during the process depends upon the conditions selected. In some cases, most of the oxygen is consumed. In others, significant excesses of oxygen are 5 required for complete conversion of fluorenes to fluorenones. The exact conditions are readily determined by routine experimentation.
• the process of this invention can be carried out in any type of reactor, which is not attacked under the reaction conditions and which does not interact deleteriously with the reactants, solvent or products. Accordingly, the process can be carried out in glass reactors, o stainless steel reactors, fluorocarbon lined reactors, and tubes or pipes lined with glass, plastic or rubber.
• the reactors are advantageously provided with stirring means, or the reactors are advantageously rocked or shaken to provide contact between the materials in the reaction mixture. Alternatively or simultaneously, it is advantageous to provide agitation by use of a 5 circulating pump.
• a stirring means for example, impeller, in the organic phase.
• the process of this invention can be done in batch or continuous mode.
• Continuous reactions can be done in cocurrent flow mode, countercurrent flow mode or crosscurrent flow mode, of which cocurrent flow mode, corresponding to plug flow conditions, 0 is preferred when appropriate equipment is more readily available.
• Continuous reactions can also be done in stirred tank reactors or packed or agitated column reactors, of which the latter are preferred.
• Another preferred embodiment is to carry out the process of this invention in continuous mode, using a column packed with sodium hydroxide or potassium hydroxide 5 solids, preferably pellets.
• the continuous process is preferably done using oxygen as the oxidizing gas, preferably under pressure from ambient to about 10 bars.
• the oxidations are carried out in countercurrent flow mode, using a stream of fluorene compound in heterogeneous nitrogenous solvent flowing in a direction opposite to streams of air/oxygen and a concentrated aqueous solution of alkali metal hydroxide
• phase-transfer agent or phase-transfer catalyst
• Materials falling within this definition are generally quaternary salts, for example, quaternary ammonium or phosphonium o salts
• phase-transfer agents/catalysts has been set forth by Ma, Szeverenyi et al , Finger and Pearson, supra
• An advantageous feature of the process of this invention is the ease with which the fluorenone product can be isolated If after removal of solids the reaction mixture appears as one phase, solvent is removed from the mixture, for example, using a rotary evaporator The 5 residue from which solvent has been removed is cooled to induce crystallization of fluorenone compound and crystalline fluorenone product is removed by filtration Extremely high purity fluorenone can be isolated by washing the crude crystalline fluorenone with solvents such as hydrocarbon solvents, preferably aliphatic more preferably having from 5 to 7 carbon atoms or alcohol solvents, preferably having from 1 to 6 carbon atoms, most preferably hexane, 0 cyclohexane, isopropanol, methanol, or ethanol
• solvents such as hydrocarbon solvents, preferably aliphatic more preferably having from 5 to 7 carbon atoms or alcohol solvents, preferably having from 1 to 6 carbon atoms, most preferably hexane, 0 cyclohex
• the water layer is preferably separated and discarded or recycled
• the organic layer, containing the fluorenone product, is processed as explained for the one-phase reaction mixture
• the process of this invention is one wherein the process is carried out in continuous mode in a column packed with potassium hydroxide solids, preferably pellets, the oxidizing gas is oxygen under a pressure from ambient to about 10 bars 0 (1000 kPa), the heterocyclic nitrogenous solvent is pyridine, the fluorene compound is fluorene or a crude fluorene concentrate and the temperature is from 20°C to 45°C
• Another highly preferred embodiment is a batch process of the invention wherein the oxidizing gas is introduced under pressure into a stirred reactor containing a continuous organic phase containing droplets of aqueous sodium or potassium hydroxide 5 wherein the aqueous solution is at least about 40 percent by weight potassium hydroxide, the oxidizing gas is air, and the temperature is from 40°C to 65°C
• the process of this invention is carried out in continuous mode in a stirred reactor, wherein a solution of fluorene or crude fluorene concen- trate in pyridine is contacted in countercurrent flow mode with an aqueous solution of at least about 40 percent by weight of sodium or potassium hydroxide, the oxidizing gas is a mixture of air and oxygen, and the temperature is from 40°C to 65°C
• the reaction was done in a 1000-mL cylinder (100 mm in diameter, 140 mm in height), equipped with a 50 mm diameter turbine impeller driven by a vertical shaft
• the stirring rate was measured by a tachometer
• the temperature was controlled by a 3 04 meter by 0 635 cm external diameter coil, immersed in the reaction medium, through which coolant, maintained at a constant temperature by a circulating refrigerated/heated bath, was pumped
• the temperature was measured by a thermocouple inside a thermowell which runs the entire depth of the reactor
• the reactor was also equipped with a nitrogen inlet which was used to maintain a nitrogen atmosphere above the reaction mixture
• the entire apparatus was constructed of fluorocarbon resin commercially available from E I du Pont de Nemours & Co under the trade designation Teflon ® PFA
• the reactor was flushed with nitrogen and KOH (85 percent, contained 15 percent water, A C S reagent grade, 39 0 g, 0 59 mole, crushed in a mortar with pestle), followed by a solution consisting of fluorene (3400 g, 0.205 mole) and pyridine (291.6 g, 3 686 mole, 304 0 mL) was charged to the reactor
• the stirrer was started and the speed adjusted to 700 rpm
• the coolant was admitted to the coils and the temperature of the reaction solution was adjusted to 15°C
• the air flow was started and adjusted to 2831 60 mL/minute as measured by a rotameter
• the start of the air flow was considered to be time 0 for the reaction
• the reaction mixture was sampled after 10 minutes and analyzed by gas chromatography (GC) on a Va ⁇ an 3400 GC equipped with a 30 meter by 0 53 mm Megabore (Trademark of J & W Scientific Inc ) capillary column coated with
• the start of the air flow was considered to be time 0 for the reaction.
• the reaction mixture was sampled after 60 minutes and analyzed by gas chromatography (GC) on a Varian 3400 GC equipped with a 30 meter by 0.53 mm Megabore (Trademark of J & W Scientific Inc.) capillary column coated with a 3-micron film of DB-624 as the stationary phase and a flame ionization detector (FID, Varian 3400).
• GC gas chromatography
• FID flame ionization detector
• the stirring was stopped and the phases allowed to separate.
• the organic phase was decanted and placed on the rotary evaporator to remove pyridine to less than 0.5 percent of the mass (by GC).
• the resulting oil was allowed to cool to 25°C and the resulting crystals of fluorenone are collected on a fritted filter.
• the dried crystals weigh 57.85 g (98.67 percent of theory).
• the oxygen content of the gas stream was 1.58 mole of oxygen (in 226,528 mL of air passing through the reactor during the three hour reaction time).
• Example 1 The reactor of Example 1 was flushed with nitrogen. Potassium hydroxide (85 percent, contained 15 percent water, A.C.S reagent grade, 39.0 g, 0.59 mole, crushed in a mortar with pestle) was charged to the reactor, followed by a solution consisting of fluorene (54.08 g, 0.325 mole) and pyridine (216.3 g, 2.73 mole, 221 mL). The stirrer was started and the speed adjusted to 2000 rpm. The coolant was admitted to the coils and the temperature of the reaction mixture was adjusted to 30.4°C. The air flow was started and adjusted to 943.87 mL/minute (0.008826 mole/minute of contained oxygen) as measured by a rotameter. The start of the air flow was considered to be time 0 for the reaction.
• Potassium hydroxide 85 percent, contained 15 percent water, A.C.S reagent grade, 39.0 g, 0.59 mole, crushed in a mortar with pestle
• the reaction mixture sampled after 60 minutes and analyzed by gas chromatography (GC, Varian 3400 GC equipped with a 30 meter by 0.53 mm Megabore [Trademark of J & W Scientific Inc.] capillary column coated with a 3 micron film of DB-624 as the stationary phase and a flame ionization detector (FID, Varian 3400).
• the reaction mixture contained 14.13 percent by weight of fluorene and 85.87 percent by weight of 9-fluorenone. After two hours' reaction, the reaction mixture contained no detectable fluorene and 100 percent of 9-fluorenone.
• the oxygen flow was started and adjusted to 37.75 mL/minute (0.101 1 mole/hour of oxygen) as measured by a rotameter. The start of the oxygen flow was considered to be time 0 for the reaction.
• reaction mixture sampled and analyzed after 60 minutes, as described in Example 3, contained 14.78 percent by weight of fluorene and 85.22 percent by weight of
• Example 30 The reactor, described in Example 1 , was flushed with nitrogen. To the reactor was charged NaOH pellets (98.4 percent, A.C.S reagent grade, 29.4 g, 0.736 mole) followed by a solution consisting of fluorene (29.4 g, 0.177 mole) and pyridine (294.0 g, 3.717 mole, 300 mL). The stirrer was started and the speed adjusted to 800 rpm. The coolant was admitted to the coils and the temperature of the reaction solution was adjusted to 40.1°C. The oxygen flow was
• Example 35 started and adjusted to 37.75 minute (0.101 1 mole/hour of oxygen), as measured by a rotameter.
• the start of the oxygen flow was considered to be time 0 for the reaction.
• the reaction mixture sampled after 60 minutes and analyzed by gas chromatography as in Example 3, contained 24.09 percent fluorene, and 75.91 percent of 9-fluorenone.
• the reaction mixture after 2 hours, 20 minutes, contained no detectable fluorene and 100 percent of 9-fluorenone.
• the amount of oxygen, passed through the reaction mixture was 0.232 mole of oxygen .
• the fluorenone product was isolated as in Example 3.
• Example 6 - Oxidation Using 50 Percent Sodium Hydroxide Solution as the Base The reactor of Example 1 was flushed with nitrogen, as above.
• the reaction mixture was sampled and analyzed as in Example 3. After 60 minutes, the mixture contained 31 .10 percent of fluorene, and 68.90 percent of 9-fluorenone. The reaction mixture, sampled again after 2 hours, 30 minutes, contained 1.84 percent of fluorene and 98.16 percent of 9-fluorenone. After 4 hours, 30 minutes, the mixture contained no detectable fluorene and 100 percent of 9-fluorenone. The amount of oxygen, passed through the reaction mixture, was 0.455 mole of oxygen. The product was isolated as in Example 3. Example 7 - Oxidation Using Soda Lime as the Base
• Example 1 The reactor of Example 1 was flushed with nitrogen. To the reactor was charged soda lime (4 to 8 mesh, Certified A.C.S., 29.4 g, entry no. 851 1 , "The Merck Index, " Eleventh Ed., 1989), followed by a solution consisting of fluorene (29.4 g, 0.177 mole) and pyridine (294.0 g, 3.717 mole, 300 mL). The stirrer was started and the speed adjusted to 800 rpm. The coolant was admitted to the coils and the temperature of the reaction solution was adjusted to 40.1 C C The oxygen flow was started and adjusted to 37.75 mL/minute (0.101 1 mole/hour of oxygen) as measured by a rotameter. The start of the oxygen flow was considered to be time 0 for the reaction.
• the reaction mixture sampled and analyzed as in Example 3, at 60 minutes contained 31.10 percent of fluorene and 67.28 percent of 9-fluorenone. At the end of 2 hours, 30 minutes, the reaction mixture contained 4.21 percent of fluorene and 95.79 percent of 9-fluorenone. After 4 hours, 10 minutes, the reaction mixture contained no detectable fluorene and 100 percent of 9-fluorenone. The amount of oxygen, passed through the reaction mixture, was 0.420 mole of oxygen. The product was isolated as in Example 3.
• Example 1 The reactor of Example 1 was flushed with nitrogen. To the reactor was charged calcium hydroxide (powder, Certified USP, 29.4 g, 0.397 mole), followed by a solution consisting of fluorene (29.4 g, 0.177 mole) and pyridine (294.0 g, 3.717 mole, 300 mL). The stirrer was started and the speed adjusted to 800 rpm. The coolant was admitted to the coils and thetemperature of the reaction solution was adjusted to 40 1°C. The oxygen flow was started and adjusted to 37.75 mL/minute (0.101 1 mole/hour of oxygen), as measured by a rotameter. The start of the oxygen flow was considered to be time 0 for the reaction.
• Example 9 Oxidation Method Using Lithium Hydroxide as the Base
• the reactor of Example 1 was flushed with nitrogen.
• To the reactor was charged lithium hydroxide (powder, 29.4 g, 1.228 mole), followed by a solution consisting of fluorene (29.4 g, 0.177 mole) and pyridine (294.0 g, 3.717 mole, 300 mL).
• the stirrer was started and the speed adjusted to 800 rpm.
• the coolant was admitted to the coils and the temperature of the reaction solution was adjusted to 40.1°C.
• the oxygen flow was started and adjusted to 37.75 mL/minute (0.101 1 mole/hour of oxygen), as measured by a rotameter. The start of the oxygen flow was considered to be time 0 for the reaction.
• Example 10 Oxidation Using Alumina as the Base
• Example 1 The reactor of Example 1 was flushed with nitrogen. To the reactor was charged alumina 4126 (0.1587 cm extrudate, 29.4 g), followed by a solution consisting of fluorene (29.4 g, 0.177 mole, 300 mL). The stirrer was started and the speed adjusted to 800 rpm. The coolant was admitted to the coils and the temperature of the reaction solution was adjusted to 40. TC. The oxygen flow was started and adjusted to 37.75 mL/minute (0.101 1 mole/hour of oxygen), as measured by a rotameter. The start of the oxygen flow was considered to be time 0 for the reaction.
• Example 1 1 - Oxidation Using Talc as the Base
• talc purified grade, powder, 29.4 g
• a solution consisting of fluorene 29.4 g, 0.177 mole
• pyridine 294.0 g, 3.717 mole, 300 mL
• the stirrer was started and the speed adjusted to 800 rpm.
• the coolant was admitted to the coils and the temperature of the reaction solution was adjusted to 40.1°C.
• the oxygen flow was started and adjusted to 37.75 mL/minute (0.101 1 mole/hour of oxygen), as measured by a rotameter. The start of the oxygen flow was considered to be time 0 for the reaction.
• reaction mixture sampled after 60 minutes and analyzed by gas chromatography as in Example 3, contained 98.47 percent of fluorene and 1.53 percent of 5 9-fluorenone. After 204 minutes, reaction mixture contained 96.73 percent of fluorene and 3.27 percent of 9-fluorenone. The reaction was terminated at this point.
• Example 12 Oxidation Using 50 Percent Sodium Hydroxide as the Base With Crude Fluorene Concentrate (Contained 55 Percent of Fluorene)
• Example 1 The reactor of Example 1 was flushed with nitrogen. To the reactor was charged 10 NaOH (50 percent, contained 50 percent water, A.C.S reagent grade, 60.1 g dry weight, 1 .50 mole, 78.6 mL) followed by a solution consisting of fluorene concentrate (120.0 g of concentrate, 0.397 mole) and pyridine (483.8 g, 6.12 mole, 495 mL). The stirrer was started and the speed adjusted to 800 rpm. The coolant was admitted to the coils and the temperature of the reaction solution was adjusted to 38.4 ⁇ C. The oxygen flow was started and adjusted to 15 37.75 mL/minute (0.101 1 mole/hour), as measured by a rotameter. The start of the oxygen flow was considered to be time 0 for the reaction.
• 10 NaOH 50 percent, contained 50 percent water, A.C.S reagent grade, 60.1 g dry weight, 1 .50 mole, 78.6 mL
• the reaction mixture sampled after 60 minutes and analyzed by gas chromatography as in Example 3, contained 56.1 1 percent of the original fluorene; 43.89 percent of the original fluorene had been converted to 9-fluorenone.
• the reactor was a 2.54 cm diameter section of pipe, 60.9 cm in length, packed to a depth of a 55.8 cm with a bed of KOH pellets (85 percent, contained 15 percent water, A.C.S. 30 reagent grade, 337.3 g, 6.01 mole).
• the temperature was measured by a thermocouple inside a thermowell, running the entire length of the reactor.
• the reactor was also equipped with a gas inlet at the bottom, through which a nitrogen atmosphere was maintained, until the oxidation was begun. The gas was changed to air during the reaction period.
• a second inlet at the base of the reactor was used to introduce the reaction mixture at a constant rate by means of a 35 metering pump.
• a feed reservoir 2 liters in volume was connected to the suction port of the metering pump.
• the entire apparatus was constructed of fluorocarbon resin commercially available from E.I. du Pont de Nemours & Co. under the trade designation Teflon ® PFA.
• the reaction mixture was collected at the overflow of the reactor column and was sampled at intervals and analyzed as in Example 3 by GC After 160 minutes, the reaction mixture contained 90 64 percent of pyridine, 3 61 percent of fluorene, and 7 09 percent of 9-fluorenone (66 26 percent of the original fluorene converted to 9-fluorenone) After 330 minutes, the reaction mixture contained 90 49 percent of pyridine, 3 42 percent of fluorene, and 7 28 percent of 9-fluorenone (69 04 percent conversion of fluorene to 9-fluorenone) The reaction was continued until all of the material in the feed reservoir had been consumed (1290 minutes) A sample of the reaction mixture, analyzed as in Example 3, contained 90 38 percent of pyridine, 3 15 percent of fluorene, and 7 55 percent of 9-fluorenone (70 56 percent conversion) No other oxidation products were detected Results are given in Table I Example 14 - Continuous Oxidation
• the reactor was flushed with nitrogen, after which a solution containing 9 98 percent by weight fluorene in pyridine (401 O g) was charged to the feed reservoir
• the metering pump was set to pump at 1 O mL/minute and energized to pump solution to the reactor
• the oxygen flow was started and adjusted to 377 54 mL/minute (1 01 mole/hour oxygen), as measured by a rotameter
• the start of the oxygen flow was considered to be time 0 for the reaction
• the temperature was 27 5°C
• the reaction mixture was collected at the overflow of the reactor column and analyzed as in Example 3 After 70 minutes, the reaction mixture contained 90 89 percent of pyridine, 0 79 percent of fluorene, and 10 06 percent of 9-fluorenone (92 72 percent of the original fluorene converted to 9-fluorenone
• the reaction mixture was sampled again after 330 minutes and analyzed as above
• the reaction mixture contained 90 89 percent of pyridine, 1 51 percent of fluorene
• the reactor was a 2 54 cm diameter stainless steel tube, 182 8 cm in length ⁇ equipped with a 60 inch (152 4 cm) packed bed containing KOH (85 percent, contained 15 percent water, A C S reagent grade, 758 9 g, 13 5 mole)
• the temperature was measured by a thermocouple inside a thermowell, running the entire length of the reactor
• the reactor was also equipped with a gas inlet at the lower end, which was used to maintain a nitrogen atmosphere in the reaction solution until the reaction was begun The gas inlet then delivers oxygen for the reaction
• a second inlet at the base of the reactor was used to introduce the reaction mixture at a constant rate by means of a metering pump
• the entire apparatus was constructed of type 316 stainless steel
• the reactor was flushed with nitrogen, whereupon a solution containing 11 28 ⁇ percent by weight of fluorene in pyridine was charged to the feed reservoir
• the metering pump was set to pump at 1 0 mL/minute and energized to initiate flow of solution to the reactor
• the oxygen flow was started and adjusted to 47 19 mL/m ⁇ nute (1 01 mole/hour oxygen), as measured by a rotameter
• the start of the oxygen flow was considered to be time 0 for the reaction
• the temperature, as measured by the thermocouple, was 23 6°C
• the reaction mixture was collected at the overflow of the reactor column and was sampled at intervals and analyzed as in Example 3 by GC After 120 minutes, the reaction mixture contained 0 55 percent of fluorene, and 10 73 percent of 9-fluorenone (95 12 percent of the original fluorene converted to 9-fluorenone) The reaction mixture, after 260 minutes, contained 1 57 percent of fluorene and 9 71 percent of 9-fluorenone (86 08 percent of the original fluorene converted to 9-fluorenone) The reaction was continued until all of the material in the feed reservoir was consumed (380 minutes) At this point, the reaction mixture contained 3 00 percent of fluorene and 8 28 percent of 9-fluorenone (73 40 percent of the original fluorene converted to 9-fluorenone) No other oxidation products were detected Results of the experiments are given in Table III
• the reactor was a 2 54 cm diameter, section of stainless steel tube, 182 8 cm in length and packed to a depth of 152 4 cm with KOH pellets (85 percent, contained 15 percent water, A C S reagent grade, 758 9 g, 13 5 mole)
• the temperature was measured by a thermocouple inside a thermowell, which runs the entire length of the reactor
• the reactor was also equipped with a gas inlet at the base A nitrogen atmosphere was maintained in the reaction solution until the reaction was begun, after which the gas inlet delivered oxygen for the reaction
• a second inlet at the base of the reactor was used to introduce the reaction mixture at a constant rate by means of a metering pump
• the feed reservoir 10 L in volume
• the entire apparatus was constructed of type 316 stainless steel
• the reactor was flushed with nitrogen before a solution containing 1 1 28 percent by weight of fluorene in pyridine was charged to the feed reservoir
• the metering pump was set to pump at a rate of 1 0 mL/minute and energized to begin flow of solution to the reactor
• the oxygen flow was started and adjusted to 28 32 mL/minute (0 076 mole/hour oxygen), as measured by a rotameter
• the start of the oxygen flow was considered to be time O for the reaction
• the exit port of the reactor was restricted to maintain the pressure within the reactor at 2 75 bars (275 kPa)
• the temperature, as measured by the thermocouple, was 25 3°C
• reaction mixture was collected at the overflow of the reactor column and was sampled at intervals and analyzed by GC, as in Example 3 After 154 minutes, the reaction mixture contained 2 30 percent of fluorene and 8 98 percent of 9-fluorenone (79 61 percent of the original fluorene converted to 9-fluorenone) The reaction was continued until all ofthe material in the feed reservoir was consumed (394 minutes) The reaction mixture contained 1 90 percent of fluorene and 9 38 percent of 9-fluorenone (83 16 percent of the original fluorene converted to 9-fluorenone) No other oxidation products were detected Results for the run are given in Table IV
• the reactor was a 2 54 cm diameter stainless steel tube, 182 8 cm in length and packed to a height of 152 4 cm with KOH pellets (85 percent, contained 15 percent water, A C S reagent grade, 758 9 g, 13 5 mole)
• the temperature was measured by a thermocouple inside a thermowell, which runs the entire length of the reactor
• the reactor was also equipped with a gas inlet atthe base to maintain a nitrogen atmosphere in the reaction solution until the reaction was begun, at which point oxygen for the reaction was delivered to the reactor
• a second inlet at the base of the reactor was used to introduce the reaction mixture at a constant rate by means of a metering pump
• the entire apparatus was constructed of type 316 stainless steel
• the reactor was flushed with nitrogen before a solution containing 22 16 percent by weight of fluorene in pyridine was charged to the feed reservoir
• the metering pump was set to pump at 1 4 mL/minutes and energized to begin flow of the solution to the reactor
• the oxygen flow was started and adjusted to 23 60 mL/minute (0 063 mole/hour oxygen), as measured by a rotameter
• the start of the oxygen flow was considered to be time O for the reaction
• the exit port of the reactor was restricted to maintain the pressure within the reactor at 2 97 bars (297 kPa)
• the temperature, as measured by the thermocouple, was 43 1°C
• the reaction mixture was collected at the overflow of the reactor column and was sampled at intervals, as above After 80 minutes, the reaction mixture contained 0 0 percent of fluorene and 22 16 percent of 9-fluorenone ( 100 00 percent of the original fluorene was converted to 9-fluorenone)
• the reaction was continued until all of the material in
• Air flow was initiated and adjusted to 943 86 mL/minute (0 088 mole/mm) as measured by a rotameter The initiation of air flow was time O for the reaction
• the reaction mixture was sampled after 60 minutes and analyzed by gas chromatography (GC) on a Varian 3400 GC equipped with a 30 m by 0 53 mm Megabore (Trademark of J & W Scientific Inc ) capillary column coated with a 3-m ⁇ cron film of DB-624 as the stationary phase and a flame lonization detector (Varian 3400)
• the reaction mixture contained 63 79 percent of fluorene and 17 60 percent of 9-fluorenone (21 62 percent conversion of fluorene)
• the mixture contained 14 41 percent of fluorene and 66 98 percent of 9- fluorenone (82 32 percent conversion of fluorene)
• the reaction mixture contained no detectable fluorene and 81 39 percent of 9-fluorenone ( 100
• Example 19 Oxidation Of Fluorene By Air Using 50 Percent Sodium Hydroxide Solution, Effect of Improved Air Dispersion
• the reactor was a 3000-mL cylinder (200 mm diameter, 140 mm tall) equipped 0 with a bottom drain to which was attached a centrifugal pump (March Manufacturing Model RC-2CP-MD), which discharged to a return line 1 1 mm in diameter
• the return line carried the reaction solution to the top of the reactor Air was fed to the reactor via a tee in the return line at about halfway up the height of the reactor
• Temperature was maintained at a constant temperature by a cooled/heated bath which pumped heat exchange fluid through a jacket 5 surrounding the reactor
• the reactor was also equipped with a nitrogen inlet for maintaining a nitrogen atmosphere over the reaction mixture
• the entire apparatus was constructed of a fluorocarbon resin commercially available from E I du Pont de Nemours & Co under the trade designation Teflon ® PFA
• aqueous sodium 0 hydroxide solution (A C S reagent grade, 46 57 g dry weight, 93 14 g of solution, 1 16 mole) was charged to the reactor followed by a solution of fluorene (20 g, 0 12 mole) in pyridine ( 193 52 g, 189 26 mL, 2 45 mole)
• the pump was turned on and the solution was allowed to become homogeneous Coolant was admitted to the jacket and the temperature of the reaction mixture was adjusted to 30 4°C 5
• Air flow was initiated and adjusted to 943 86 mL/minute (0 088 mole/mm) as measured by a rotameter The initiation of air flow was time 0 for the reaction
• the reaction mixture was sampled after 60 minutes and analyzed by gas chromatography (GC) on a Varian 3400 GC equipped with a 30 m by 0 53 mm Megabore (Trademark of J & W Scientific Inc ) capillary column coated with a 3-m ⁇ cron
• Example 19 The reactor and procedure of Example 19 were used To the reactor was charged 50 percent aqueous sodium hydroxide solution (A C S reagent grade, 4.81 g dry, 9 62 g solution, 0 12 mole), followed by a solution of 20 g of fluorene (0 1 2 mole) and 180 g (2 28 mole, 176 04 mL) of pyridine The rate of air flow was 943 86 mL/minute (0 0088 mole/ minute of oxygen)
• reaction mixture contained 57.21 percent of fluorenone and 42 79 percent of 9-fluorenone (42 79 percent conversion) At the end of 120 minutes, the mixture contained 19 64 percent of fluorene and 80 36 percent of 9-fluorenone (80.36 percent conversion) At the end of 4 hours, the mixture contained no detectable fluorene ( 100 percent conversion to
• Example 19 The apparatus and method of Example 19 was used To the reactor was charged 50 percent aqueous sodium hydroxide solution (A C S reagent grade, 48 13 g dry, 96 26 g of solution, 1 20 mole), followed by a solution of 20 g (0 12 mole) of fluorene, 4,4-
• Example 19 The reactor and method of Example 19 were used To the reactor was charged 50 percent aqueous sodium hydroxide solution (4 87 g dry, 9 74 g of solution, 0 12 mole), followed
• reaction mixture contained 35 51 percent of fluorene and 12 64 percent of 9-fluorenone (26.25 percent conversion) After 2 hours, the mixture contained 30 37 percent of fluorene and 17 78 percent of 9-fluorenone (36 93 percent conversion) At the end
• the reactor was a vertical 5 08 cm diameter pipe constructed of fluorocarbon
• the reactor comprised 12 stirred sections, each 1.75 cm long, separated by horizontal spacers (0 64 cm thick) each perforated with eight holes (0 64 cm diameter) to permit communication between the sections Centered within each stage was an impeller, mounted on a vertical drive shaft of type 316 stainless steel (0 954 cm height per section, 1 651
• the impeller was driven by an air motor at a constant speed of 1000 rpm
• Each stirred section had a volume of about 100 mL
• the uppermost of the stirred sections contained a port for introduction of reactants and removal of products and a thermowell for measuring the temperature of the reactor contents Additional thermowells were placed in stage four (from top) and just below stage six.
• the lowest stirred section contained a port for introduction of reactants and removal of products.
• At the bottom of the reactor was a tee joint, connected to a bottom drain on one leg for removal of reactor contents and to ports for introducing feed solution and oxidizing gas. After the reactor was purged with nitrogen, pyridine (400 mL) was charged to the reactor to a level slightly above the bottom of the sixth stage.
• the stirrer was turned on (1000 rpm).
• Sodium hydroxide (50 percent by weight) was metered into the reactor at a rate of 1.26 mL/minute.
• fluorene in pyridine (20 percent by weight of fluorene) was fed to the first stage through a metering pump at a rate of 2.25 mL/minute.
• the combined flow rate was 3.51 mL/minute, resulting in a residence time of 5.13 hours.
• Air and oxygen were introduced into the bottom stage in a 1 : 1 volume ratio at a rate of 94.38 mL/minute. Vent gas was released through a control valve which regulated the pressure to 2.83 bars (283 kPa).
• the product solution was collected at the top overflow and analyzed by GC as in Example 19. The following results are given in Table VI.
• the organic phase from a reaction mixture was collected. Pyridine in the mixture was removed by batch distillation or using a failing film still (120°C/343 mm Hg (46 kPa)). Any water present in the organic phase was removed as an azeotrope with pyridine. After the pyridine had been removed, the crude fluorenone was cooled in a batch crystallizer to crystallize fluorenone (about 10°C). Fluorenone was isolated by filtration. The crystalline mass was washed with a solvent and the recovery and purity of the washed crystalline mass was determined (GC) The following results were obtained
• COMPOSITION percent fluorenone 20 initial 58 25 58 25 58 25 58 25 58 25 58 25 58 25 58 25 58 25 58 25 58 25
• the temperature was measured by a thermocouple inside a thermowell which runs the entire depth of the reactor
• the reactor was also equipped with a nitrogen inlet which was used to maintain a nitrogen atmosphere above the reaction solution
• the o apparatus was constructed of Hastaloy C
• the reactor was flushed with nitrogen, thenKOH (50 percent aqueous, A C S reagent grade, 77 42 g solution weight, 0 69 mole) followed by a solution consisting of fluorene concentrate (57 percent fluorene, 20 12 g, contained 0 07 mole fluorene) and pyridine (45 87 g, 0 58 mole, 44 86 mL) was charged to the reactor
• the stirrer was started and 5 the speed adjusted to 550 rpm
• the temperature controller was switched on and the temperature of the reaction solution was adjusted to 40°C
• the air flow was started and adjusted to 0 2 SCFH (standard cubic feet per hour, 94 mL/minute at atmospheric pressure and 25°C, 0 00088 moles/minute of contained oxygen) as measured by a rotameter
• the vent gas was released through a control valve which regulated the pressure in the reactor to 70 psig (5 8 0 bars, 580 kPa) absolute)
• Example 26 Selectivity of Oxidation Method in Producing Very High Purity (> 99.6 Percent) BHPF From a Crude Fluorene Concentrate (60 Percent fluorene)
• a sample of starting material contained 60 percent fluorene by GC analysis. This crude fluorene concentrate (50.54 g, contained 0.18 mole) was dissolved in pyridine (282.72 g, 3.57 mole) to give a 9.1 percent weight/weight solution in pyridine.
• the reactor described in Example 1 was used.
• reaction mixture was stripped of the pyridine, and 31.5 g of the resulting fluorenone containing solids (contained 0.1 13 mole fluorenone) are dissolved in phenol to give a molar ratio of phenol (85.50 g, 0.91 mole) to fluorenone of 8 to 1.
• Example 27 This Example of Our Oxidation Method Showed the Utility of this Very Selective Oxidation Method in Producing Very High Purity ( >99.6 percent) BHPF From a Crude Fluorene Concentrate (80 Percent fluorene)
• Example 1 The reactor described in Example 1 was flushed with nitrogen, then NaOH (50 percent aqueous, A.C.S reagent grade, 76.5 g dry weight, 153.0 g solution weight, 1.91 mole) followed by a solution consisting of fluorene concentrate (fluorene concentrate containing 80 percent fluorene obtained from Deza Corporation, Valasske Meririci, Czech Republic) ( 100.0g concentrate, 0.48 mole) and pyridine (300. Og, 3.79 mole, 307 mL) was charged to the reactor. The stirrer was started and the speed adjusted to 1000 rpm. Coolant was admitted to the coils, and the temperature of the reaction solution was adjusted to 42°C.
• fluorene concentrate fluorene concentrate containing 80 percent fluorene obtained from Deza Corporation, Valasske Meririci, Czech Republic
• 100.0g concentrate, 0.48 mole 100.0g concentrate, 0.48 mole
• pyridine 300. Og, 3.79 mole, 307
• the oxygen flow was started and adjusted to 0.2 SCFH (standard cubic feet per hour, 94.38 mL/minute at 25°C and atmospheric pressure, 0.0042 moles/minute of oxygen) as measured by a rotameter.
• the start of the oxygen flow was considered to be time 0 for the reaction.
• the reaction mixture was sampled after 60 minutes and analyzed by gas chromatography (GC) on a Varian 3400 GC equipped with a 30 meter by 0.53 mm Megabore o (Trademark of J & W Scientific Inc.) capillary column coated with a 3-micron film of DB-624 as the stationary phase and a flame ionization detector (FID)(Varian 3400).
• GC gas chromatography
• FID flame ionization detector
• reaction was sampled 5 again after 4.5 hours and analyzed as before which showed that the reaction mixture now contained no detectable fluorene for 100 percent conversion of the starting fluorene to 9-fluorenone. No other products of oxidation were detected. 1.14 Moles of oxygen had been passed through the reactor during the four hour 30 minute reaction time.
• Methylene chloride (122 g) was added and the mixture heated to dissolve solids. All but a few small clumps dissolve. More methylene chloride (1 13 g) was added to help dissolve remaining solids then the mixture was passed through a paper filter to remove excess solids. The mixture was then allowed to cool to room temperature while stirring and 5 crystallization was observed.
• the brown slurry 208 g was poured into a medium fritted filter and filtered by suction. When the filtrate was reduced to a slow drip the filtration was stopped. An amount, 160 g, of brown filtrate was recovered. The resulting cake was yellow/green in color. Methylene chloride (56 g) was slowly added to the top of the cake, and the cake was displacement washed. Washing improved the color greatly.
• the wet cake was analyzed by liquid chromatography (LC) and determined to be comprised of 99.6 percent p,p-B HPF relative to isomers, adducts and other hydrocarbons (excluding methylene chloride).
• Example 28 Selectivity of Oxidation Method in Producing Very High Purity ( > 99.8 percent) BHPF From A Crude Fluorene Concentrate (80 percent Fluorene)
• the reactor described in Example 1 was flushed with nitrogen, then NaOH (50 percent aqueous, A.C.S reagent grade, 76.5 g dry weight, 153.0 g solution weight, 1 .91 mole) followed by a solution consisting of fluorene concentrate (fluorene concentrate containing 80 percent fluorene obtained from Rutgers- VfT AG, Kekulestase 30, D-44579 Castrop-Rauxel, Germany) (100.0 g concentrate, 0.48 mole) and pyridine (300.0 g, 3.79 mole, 307 mL) was charged to the reactor.
• fluorene concentrate fluorene concentrate containing 80 percent fluorene obtained from Rutgers- VfT AG, Kekulestase 30, D-44579 Castrop-Rauxel, Germany
• the stirrer was started and the speed adjusted to 1000 rpm.
• the coolant was admitted to the coils and the temperature of the reaction solution was adjusted to 42°C.
• the oxygen flow was started and adjusted to 0.2 SCFH (standard cubic feet per hour, 94.38 mL/minute at 25°C and atmospheric pressure, 0.0042 moles/minute of oxygen.) as measured by a rotameter.
• the start of the oxygen flow was considered to be time O for the reaction.
• the reaction mixture was sampled after 60 minutes and analyzed by gas chromatography (GC) on a Varian 3400 GC equipped with a 30 meter by 0.53 mm Megabore (Trademark of J & W Scientific Inc.) capillary column coated with a 3-micron film of DB-624 as the stationary phase and a flame ionization detector (FID)(Varian 3400).
• GC gas chromatography
• FID flame ionization detector
• reaction was sampled again after 3.5 hours and analyzed as before which showed that the reaction mixture now contained no detectable fluorene for 100 percent conversion of the starting fluorene to 9-fluorenone. No other products of oxidation were detected.
• An amount, 0.88 moles, of oxygen were passed through the reactor during the 3 hour 30 minute reaction time.
• the stirring was stopped and the phases allowed to separate.
• the organic phase was decanted and placed on the rotary evaporator where the pyridine was removed to less than 0.5 percent of the mass as determined by GC.
• the resulting oil was allowed to cool to 25°C.
• 100 g of methylene chloride were added to the mixture to form a homogeneous solution. Upon cooling to room temperature no precipitate was evident.
• An amount, 60 mL, deionized(DI) water were added and the mixture was distilled to remove the methylene chloride water and phenol.
• the temperature of the mixture was 137°C, the mixture was allowed to cool. Analysis of the mixture indicated a phenokBHPF mass ratio of 1 : 1.
• the mixture was approximately 80°C, approximately 100 g methylene chloride was added resulting in mild refluxing and rapid cooling.
• the wet cake was analyzed by LC and determined to be comprised of 99.8 percent p,p-BHPF relative to isomers, adducts and other hydrocarbons (excluding methylene chloride).
• the cake was placed in a vacuum oven at 85"C to 90°C for drying. Recovered product: 6.4 g.
• Example 25 The procedure of Example 25 was repeated with a impeller tip speed of 1.09 meters/seccond using a LightninTM LabMaster IITM Model TSM2010 Mixer commercially available from Mixing Equipment Company, Avon Division, a unit of General Signal which directly measured the watts input into the mixer and the ratio of organic phase to aqueous phase volumes indicated in Table VIII. Measurements of the percent conversion of fluorene to fluorenone were taken at the times indicated in Table Vlll with the impeller in the aqueous or organic phase as indicated. The results indicated in Table Vlll.
• Example 29 The procedure of Example 29 was repeated using air as oxidizing gas at atmospheric pressure, with an organic to aqueous phase volume ratio of 1.26: 1 and an impeller tip speed of 5.23 meters/second Results are shown in Table IX.
• phase-transfer catalysts especially quaternary ammonium phase - transfer catalysts, are known by those skilled in the art to degrade under oxidation conditions.
• phase-transfer catalysts degrade, their concentration decreases during a reaction, therefore, especially in continuous reactions, phase-transfer catalysts either must be used in excess or must be added as reaction progresses to maintain a sufficient concentration Furthermore, degradation of phase -transfer catalyst produces by-products which make purification of the desired oxidation product (for example, fluorenone) more difficult than it would be in the absence of such by-products

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