US2085221A - Method of making partial oxidation products - Google Patents

Description

June 29, 1937. J. H. JAMES METHOD OF MAKING PARTIAL OXIDATION PRODUCTS Original Filed Jan. 22

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R m N w m Q Q 3 Q a S m v N n w Patented June 29, 1937 UNITED STATES PATENT OFFICE METHOD OF MAKING PARTIAL OXIDATION PRODUCTS Joseph Hidy James,

Pittsburgh, Pa., assignor to Clarence P. Byrnes, trustee, Sewickley, Pa.

11 Claims. (01. 260 -116) My invention relates to the manufacture of intermediate oxidation products such as aldehyde fatty acids, from mineral oils or hydrocarbons or. their products or derivatives, whether 5 liquids or gases either alone or in mixture. Where mineral oil is used, it is preferably one of the distillates of crude mineral oil (petroleum), although the process may be applied to crude oil, or oils from shales or their distillates, or oils from low-temperature distillation of lignites or coals or other distillates.

It has heretofore been proposed to spray a mineral oil distillate into a current of air mixed with steam, this mixture being passed over as- Ilzzestos coated with finely divided copper oxide ept of the mixture. No attention was paid to the air ratio. In such a laboratory experiment a small proportion of an unknown organic acid was found in the condensed product; but the hydrocarbon used was largely consumed in keeping the catalyst layer at a red heat. Such process cannot be carried out on a practical or commercial scale as the yield is too small, the product impure,

and the hydrocarbon mainly consumed.

I have discovered that by vaporizing such oils, forming a heated mixture of the oil vapor with a proper proportion of air, either with or without steam, and passing the heated mixture through a suitable catalyst layer while keeping the reaction below that of continuous self-sustained combustion, I can produce in commercial quantities a mixture of valuable intermediate oxidation products, including aldehyde fatty acids; and can hold the reaction temperature within the proper range therefor by maintaining proper conditions.

In such process, while heat is continuously supplied to vaporize the oil, and, if necessary, additional heat is supplied to bring the mixture to the reacting temperature especially in starting;

yet the catalyst is kept below a red heat and preferably below a heat where it shows any glow, to prevent continuous self-sustained combustion which will consume a large amount of the hydrocarbon. The heat might rise temporarily to a point of ignition but in such case the yield is reduced; and the air and vapor ratio should be changed to prevent such combustion continuing. In my process there is a partial oxidation or partial combustion of the mixture within the proper range hereinafter set forth, producing intermediate combustion products including aldehyde fatty acids.

If steam is added, it will serve as a diluent to hold down the reaction zone temperature and it will aid in vaporizing heavier oils. The steam should be carefully regulated, since excess will lower the acid yield.

By long experimenting I have found that a number of inter-dependent variable conditions or factors, dependent on each other, are important in obtaining proper yields. Thus the proportion of air, the particular catalyst used, the Velocity of the current and the temperature maintained in the reaction zone are inter-dependent and should be accordingly varied in relation to each other. The thickness of catalyst is also a factor.

Heat should be continuously supplied to vaporize the oil and to preferably give an additional amount of heat, but the air ratio should be maintained, preferably above the theoretical amount; at such a rate that continuous self-sustained combustion does not occur, or steam, if it is used, can be supplied for this purpose. The reaction gives out heat and the temperature must be held down in the conversion zone. The heat may be supplied to vaporize the oil and, particularly, in starting, heat may be supplied to the catalyst by an electric resistance or otherwise, as desired.

In making aldehyde fatty acids the temperature in the conversion zone should be maintained above that at which there is a predominance of aldehydes, but below that of self-sustained combustion; although some other intermediate conbustion products including aldehydes are produced in forming aldehyde fatty acids. In making a predominance of aldehydes the temperature is somewhat lower than for acids.

3 The range of temperature for carrying out my invention and obtaining useful partial combustion products extends, so far as I have determined, from about 230 degrees C. up to about 450 degrees 0., the temperature used will depend on the hydrocarbon being treated, from heavy gasoline to the heaviest hydrocarbons that can be vaporized; and also depends on the catalytic material used, the proportion of air employed whether or not steam is added, and, to some extent, on the speed of the current mixture. I have found that the lighter the hydrocarbon treated, the higher the reaction zone temperature should be maintained, and when heavier distillates are used lower temperatures may be employed. Generally speaking for producing a predominance of aldehyde fatty acids, the upper portion of the above temperature and range is used. It will be understood, however, that I am speaking merely of predominance of percentages in the product, since in making air can approach the theoretical amount.

. aoeaaai I aldehyde fatty acids, some proportion of aldehyde is formed and vice versa.

The. catalysts hereinafter described differ in activity. With an active catalyst kept at the highest temperature consistent with a high commercial yield product, the proportion of air should be kept at or above that required by theory, the temperature, of course, being kept below that where products of complete combustion, namely, carbonic dioxide and water, form to a large extent. With more active catalysts a higher speed may be used, especially where a higher temperature within the desirable range is employed.

The time of contact with the catalyst may be lessened with the more active catalyst and with a higher temperature. With hydrocarbons of greater molecular weight, more heat must be applied to vaporize them, but the reaction zone heat should be lower. With oils of lower or less molecular weight, less heat will vaporize, but the temperature of the reaction zone should be higher. The same temperature range may, however, be used on two successive distillates with good yields. With fractions of widely different molecular weight, the difference in reaction zone temperature is marked.

The desired temperature in the reaction zone can be kept down below a glowing temperature by lowering the proportion of air nearer the theoretical amount as the temperature rises, and by raising the proportion of air as the temperature decreases, within certain limits. The more active the catalyst, or the higher the temperature within the desired range, the nearer the proportion of With less active catalysts, or with lower temperature, the greater should be the proportion of air.

The products after leaving the reaction zone are chilled and condensed or absorbed for recovering them.

As regards the catalyst employed, I prefer the complex oxides or compounds of metals having a varying valence. All parts of the complex may consist of oxides of the same metal or of different metals. For example, an excellent catalyst in this connection consists of the so-called blue oxides of molybdenum, which contain molybdenyl molybdenate, and molybdenyl molybdenite, and are probably all chemical compounds of two or more oxides of molybdenum representing different states of oxidation. These complexes may be regarded as salts; that is, compounds of one or more basic with one or more acid oxides.

Other complexes of value for such catalysts are chromic chromate, uranyl uranate, tungsten tungstate, the manganese complexes, the vanadium complexes, etc.

The basic and acid parts of these complexes may be formed from oxides of different metals, in which case, each metal, or group of metals used, should possessvarying valence. Examples of this class are:

Cobalt molybdate CeOMoOa Cobalt molybdite CeOMoOn Di-uranyl vanadate (UrOz) 2V205 etc.

Those metals, whose complexes I prefer to employ as the acid part of the catalyst, (since I have found them to be of high activity in this field), are the metals of high melting point electronegative low-atomic-volume metals having an atomic weight above 40. These metals appear on the Lothar-Meyer diagram of the periodic series beginning on the descending side of the third peak,

tantalum, tungsten and uranium. The basic oxides may be the. lower oxides of these metals or may be the oxides of iron, copper, nickel, lanthanum, cobalt, thorium and the eight or nine rare earth metals.

In both acid or basic portions there may, of course, be two or more of these combined.

With the above description of the conditions, which are varied to give the best commercial results according to ,the interaction of the factors described, I will now describe one form of apparatus for carrying out my invention.

In the drawing, 2 represents a valved air pipe through which air is supplied under pressure, 3 a meter for the air, and 4 the pipe leading from the meter into a heating and mixing vessel 5. 6 represents a vessel containing liquid hydrocarbon and 'l a valved pipe leading therefrom into the mixing vessel 5. 8 indicates a burner having a valved supply pipe 9, by which the heat may be regulated. It) represents the walls of, the furnace or heating chamber in which the retort or mixing vessel 5 is set, the heated mixture of hydrocarbon vapor and air passing from the mixing vessel through the channel H to the catalytic layer 12. This catalytic layer is shown as having a frame l2a, clamped or belted between the ends of the channel I l and the flanged end of the conduit l3, leading to a vertical condenser I4. The products emerging from the catalytic layer pass down through thetubes l5 of the condenser into the vessel l6. l1 represents the valved inlet pipe for water passing into the condenser, and IS the outlet pipe for the circulating water. The vessel I6 is provided with an outlet l9 for fumes, 20 being the valved pipe by which the condenser products are drawn off. Between the condenser and the vessel l6 and the furnace, I preferably provide an insulating screen 2|, of some heat insulator to keep the heat of the furnace away from the condensing apparatus.

22 represents a pyrometer which may be in the form of an electric couple with its wires 23 leading to an external temperature indicator 24.

As the heated mixture of vapor and air in the proper proportions passes through the catalytic layer under the regulated conditions referred to, partial oxidation or partial combustion takes place, the products being immediately taken to and through the condenser, and the desired product collecting in the vessel succeeding the condenser. The condensing apparatus may of course be of any desirable type, either in single or multiple form. I may in some cases lead pipe l9 to a scrubbing system to recover any uncondensed products.

I will now describe some specific examples of my process.

(1) Using as a catalyst blue oxides of molybdenum, the coated asbestos layer being one centimeter thick and 4.4 centimeter diameter. The oil used was a gas oil fraction distilling from 250 to 295 degrees C. The air rate was two liters per minute or 1.6 times the theoretical amount required for aldehyde fatty acid formation. The absorbers consisted of eight water bubblers. The oil was fed at the rate of 126 cubic centimeters per hour. The time of contact with the catalyst was .32 second; temperature of the catalyst was maintained at about 2'70 degrees C. duration of the run was one hour and 35 minutes. A test of the exit gas showed 2.4% of carbon dioxide and 1% of oxygen. 150 cubic centimeters of liquid oxidation products were recovered, of

which about 45% by volume consisted of aldehyde fatty acids, and about 55% by volume of alcohols, unchanged hydrocarbons, and undetermined products.

(2) The catalyst consisted of uranyl uranate and uranyl uranite on asbestos, 1.25 centimeters thick and 4.4 centimeters in diameter. The oil used was kerosene distilling at 250 to 295 degrees C. The air rate was 4 liters per minute, the condensing and absorbing system consisting of two Worm condensers and four water bubblers. The oil was entered at the rate of 200 cubic centimeters per hour. The time of contact was about .33 second. The temperature of the catalyst was maintained at about 310 degrees C. Duration of the run33 minutes. As a result 76 cubic centimeters of liquid product were recovered, which, on analysis, gave aldehyde fatty acids about 30% and aldehydes, etc., about 70%.

This run was made to show the temperature effect, the'temperature being lower than that propr for the other interdependent conditions.

In the next test, I established a more nearly correct temperature as follows:

(3) The conditions were all the same as with the second run, except that the temperature of the catalyst was maintained at about 420 degrees C. As a result of this test, 70 cubic centimeters-of liquid product were recovered which gave the following analysis: aldehyde fatty acids 42.5% aldehydes 33.70% and hydrocarbons, etc., 23.75%.

To show the effect of increasing the proportion of air in the mixture, I ran another test substantially like No. 1, above recited, except that the air was fed at the rate of about 10 liters per minute or 66 times the theoretical amount required for fatty acid formation. In this case, the oil feed was 15 centimeters per hour; the time of contact with the catalyst about .03 second; and the duration of the run about 3 hr. 20 min., the temperature of the catalyst being 260 to 280 degrees C. In this case, .756 gram of a dark tacky resinous acid mixture was recovered,

amounting to about 18% by weight of the weight of hydrocarbon treated. This shows the effect of too high a ratio of air under the conditions named.

With an apparatus for larger scale operation, practically identical with that figure in the drawing accompanying this specification, the following run was made:

Conditions (a) Catalyst: blue oxides of molybdenum on asbestos, held between parallel wire mesh screens as shown in figure, the active material packed in the disk-shaped space 15 inches in diameter and of an inch thick.

(5) Hydrocarbon mixture treated: mineral seal oil, a Pennsylvania petroleum distillate, 90% of which distilled between 250 and 324 degrees C. The distillate had a specific gravity of .8125 at 20 degrees C.

(a) Air rate: about 216 cubic feet per hour.

(d) Absorbing system: no scrubbers, only the parallel tube condenser as shown in figure.

(6) Oil feed: 2.5 gallons per hour.

(1) Time of contact of h. c. vapor-air mixture with catalyst; approximately .3 second.

(9) Temperature of catalyst: 310 to 320 degrees C. D

(h) Total time consumed in run: 2 hours.

Results (a) Carbon dioxide analysis (by volume) in exit gas stream during rur (.6%, 1.0%, .8%).

Carbon monoxide analysis .oy volume) in exit gas stream during run: (6.8%, 8.%).

(b) 3.7 gallons of product (having specific gravity at 20 degrees C. of .852) were recovered which had the following analysis; aldehyde fatty acids, 46% by volume, aldehyde 28%, leaving undetermined 26% by volume.

Actual recovery of aldehyde acids, by weight, based on weight of hydrocarbon mixture treated: 50.7%.

The above examples in connection with the description of the apparatus and operation will sufficiently disclose to those skilled in chemistry the essentials of the process, under the conditions recited above.

I believe that the aldehyde fatty acids are formed in stages, passing through intermediate stages to the desired stage. With a lower temperature and other factors suitably changed a predominance of lower oxidation products, such.

as aldehydes may be produced. The aldehyde acid stage seems to be a stable one and soaps may be made therefrom by saponifying in the usual manner, I

So far as I have found, the lowest reacting temperature for successful commercial operation can be used when the catalyzer consists of the intermediate complex compounds of oxides of molybdenum. The next lowest temperature has been used with catalysts consisting of the compounds of molybdenum with other metallic oxides of the group above named.

While a catalytic layer is important, if not essential, in obtaining commercial yields, I have found that a non-catalytic screen may be used. Even a plain tube may be used with suflicient heat supplied to it to give the desired reaction while preventing continuous self-sustained combustion. When the factors are properly arranged in such case as above recited, I have found that We can obtain a low yield of say 10 to 20% of the aldehyde fatty acids by passing the mixture through a tube, the zone of which is kept heated to a point which will give a desired reaction without causing continuous self-sustained combustion. A heated metallic screen may be used instead of heating the walls of the tube; but such processes give a relatively low yield as compared with the use of my preferred catalysts.

I consider myself to be the first to discover a practicable process of partial oxidation whereby mineral oils and their distillates may be practically and commercially converted into intermediate oxidation products in the range from alcohols to aldehyde fatty acids; and the first to discover the inter-relation, inter-dependence and proper proportions of the factors above named, to give the desired result.

The advantages of my invention will be apparent to chemists since a practicable method is afforded by which aldehyde fatty acids may be obtained in commercial quantities at a low cost. Aldehydes and other oxidation products may also be produced in commercial quantities by lowering the temperature somewhat. For example, in cases 1 and 3, by lowering the temperature of the catalytic mass to about 230 to 250 degrees C., for 1, and to 280 to 290 degrees C., for 3.

If distillates, solid at ordinary temperatures, are used, I may liquefy these hydrocarbons: by heat and then vaporize them in the process. By the terms aldehyde fatty acids and aldehyde acids herein I intend to include such forms of oxygenated organic acids as are produced by my the broader claims and that species wherein the acids predominate, whatever their form or character.

By the term "air" in my claims, I intend to cover air or oxygen or any gas containing oxygen.

Many changes may be made in the form of the apparatus employed and the catalyst used, and the important factors named may be varied within the limits above described, without departing from my invention.

By the words mineral oil in the claims, I intend to cover crude mineral oil or shale oil, or their distillates, preferably the heavier and cheaper distillates, or the products of low-temperature distillation of lignites or coals, these being generally termed aliphatic hydrocarbons of both. the saturated and unsaturated type. I do not intend to cover herein any partial combustion process relating essentially to oxidizing the class of arcmatic hydrocarbons. By the term compound in my claims relating to the catalytic material, I intend to cover either salts, compounds or oxides.

The majority of the claims to the subject matter disclosed herein are present in my Reissue Patent No. 18,522, reissued July 12, 1932 (original Patent 1,697,653 of January 1, 1929, being a continuation of this application).

I claim:

1. The process of treating hydrocarbons which comprises passing a mixture of the hydrocarbon and air over a heated catalyzer and withdrawing the products prior to complete utilization of the oxygen in oxidizing reactions.

2. In the catalytic oxidation of petroleum .hydrocarbons the step which comprises passing the reaction mixture over a catalytic mass of high heat conductivity maintained at a black heat approaching a low red heat.

3. In the catalytic oxidation of petroleum hydrocarbons the step which comprises passing the reaction mixture over a catalytic mass of substantially the heat conductivity of metallic masses and maintaining the temperature at a black heat approaching a low red heat.

4. In the catalytic oxidation of petroleum. oils the step which comprises passing a mixture of petroleum vapor and air over a composite catalyzer containing two active oxidizing agents, said catalyzer having substantially the heat conductivity of metallic masses.

5. The process of treating hydrocarbons which comprises passing petroleum vapors admixed with air through a conversion zone heated to a temperature within the range of partial oxidation and within a temperature range at which the very heat-sensitive products of oxidation are substantially retained in the materials withdrawn from the conversion zone;

6. The process of oxidizing kerosene which comprises vaporizing thisoil, passing it in admixture =with heated air into contact with a porous catalytic mass heated to an oxidizing temperature and extracting water-soluble organic acids from the products of oxidation.

- 7. The process which comprises heating a mineral oil fraction to produce' vapor thereof, ad-

mixing the vapor with a gas containing free ture in contact with a catalyst, but at a temperature below that of continuous sustained complete combustion.

9. In the manufacture of partial oxidation products, the steps comprising feeding a preheated gaseous phase mixture of aliphatic hydrocarbon and a gas containing free oxygen through a reaction zone at an elevated temperature below that of continuous self-sustained complete combustion-and within the range where partial oxidation products are produced, and recovering products from the exit stream beyond said zone of reaction.

10. In the manufacture of partial oxidation products, the steps comprising feeding a preheated gaseous phase mixture of aliphatic hydrocarbon and a gas containing free oxygen through a reaction zone in contact with a catalyst at an elevated temperature below that of continuous self-sustained complete combustion and within the range where partial oxidation products are produced, and recovering products from the exit stream beyond said zone of reaction.

11. In the manufacture of partial oxidation products, the steps consisting of preheating a gaseous phase mixture of aliphatic hydrocarbon and a gas containing free oxygen, feeding said preheated mixture through a reaction zone at an elevated temperature below that of continuous self-sustained complete combustion and within the range wherein partial oxidation products in the range from alcohols to organic acids are produced, and recovering such products from the exit stream beyond the zone of reaction.

JOSEPH HIDY JAMES.

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