US2762829A - Process for converting olefins to oxygenated organic compounds - Google Patents

Description

-a a... 4 n

'hydrocarbons from chemicals.

United States PatentO PROCESS FOR CONVERTING OLEFINS TO OXYGENA'IED ORGANIC COMPOUNDS Myron B. Kratzer, Wilmington, Del., and Karol L. Hujsak, Tulsa, Okla., assignors to -Stanolind Oil and Gas Company, Tulsa, Okla., acorporation of Delaware No Drawing. Application January 2, 1952, Serial No. 264,635

13 Claims. (Cl. 260-450) Our invention relates to a novel method for the production of oxygenated chemicals from olefins. More particularly, it includes the application of such method to the conversion of olefins present in various chemical streams whereby the olefins are transformed into more valuable chemicals by the action of steam and carbon dioxide thereon.

While the principles taught herein find application in the recovery of chemicals from numerous kinds of crude hydrocarbon mixtures, the present description deals particularly with the problems encountered in recovering valuable chemicals from the oil stream produced by the hydrogenation of carbon monoxide in the presence of a fiuidizedalkali promoted iron catalyst under known synthesis conditions. This oil fraction obtained in the hydrocarbon synthesis process contains a rather wide variety of acids, carbonyl compounds (ketones and 'aldehydes), and alcohols, together with a small proportion of esters.

Because of the proximity in boiling points of these various oil-soluble chemicals to the hydrocarbons constituting the oil fraction, separation of chemicals from hydrocarbons by normal fractional distillation methods is a practical impossibility. Normally, in the recovery of chemicals from the oil stream, the raw primary synthesis oil, as it comes from the separating unit, is treated with sufficient caustic to neutralize the acids present. There result two layers, a neutral oil layer containing the bulk of the non-acid oil-soluble chemicals and a lower aqueous layer containing the acids in the form of their corresponding salts together with an appreciable percentage, i. e., approximately 25 weight per cent of non-acid chemicals which have been solubilized thereby and from about to weight per cent of hydrocarbons, depending, of course, on the strength of the caustic initially added. While recovery of the acids from the aforesaid aqueous layer can be accomplished Without substantial difficulty, the solubilized chemicals and hydrocarbons present a rather formidable problem, especially where it is desired to effect a substantially complete separation of chemicals from hydrocarbons. Further extraction of the neutral oil layer with soap solutions formerly used, i. e., high molecular weight soaps or solutions of soaps derived from neutralizing the entire acid component of the hydrocarbon synthesis oil, failed to result in satisfactory separation of chemicals from the oil. Thus, in extracting the neutral oil containing non-acid chemicalswith such soap solutions, an extract was obtained which, on distillation followed bytopping the resulting distillate to about 110-ll5 (3., did not give a'satisfactory separation of In this procedure, the first distillate secured contained from about 10 to 12 weight per cent hydrocarbons together with essentially all of the non-acid chemicalsyand when such distillate was topped to about 110-ll5 0., there was obtained an overhead amounting to about to Weight per cent of the feed which contained only about weight per cent of the hydrocarbons in the feed. While some concentration of hydrocarbons in the light endswas effected, the hydrocarbon content of the fraction boiling above about 115? C, (bottoms) was too high to permit recovery of chemicals in a form sufficiently free from hydrocarbons to satisfy average industrial specifications. Moreover, in the distillation of non-acid chemicals from total soap mixtures, foaming frequently becomes so excessive that further separation of the chemicals from the extract is impossible.

The expression total soap appearing'in the present description is intended torefer to the mixture of soaps prepared by neutralizing the fatty acids present in the raw primary oil or the equivalent thereof.

It is an object of our invention to provide a process whereby the portion of the oil-soluble chemicalsin an olefinic hydrocarbon mixture thereof can be recovered in a substantially hydrocarbon free condition. It is a further object of our invention to provide a novel method for converting olefinic hydrocarbons into more valuable oxygenated organic chemicals wherein such olefins either constitute the sole component of the feed stream employed or are present along with relatively inert substances such as parafiin hydrocarbons.

We have now discovered that olefins can be readily converted into their corresponding oxygenated derivatives by the action of steam and carbon dioxide thereon in the presence of asuitable catalyst at elevated temperatures and pressures. In accordance with one embodiment of our invention, an olefin contaminated chemical stream, such as the overhead produced by the distillation of a soap extract obtained from the extraction of hydrocarbon synthesis oil using an aqueoussoap solution in accordance with the methods generally referred to above, is preheated to a temperature of from about 250 to 300 F. and introduced in the vapor phase along with steam and carbon dioxide into a reactor having suspended therein a dense turbulent phase consistingof a suitable finely divided catalyst. This feed contains typically from about 20 to 30 weight per cent hyrocarbons of which about to Weight per cent are olefinic. The reaction-is effected at temperature ranging from about 200 to about 700 F., preferably from about 300 to 400 F. and at pressures of from at least about 200 p. s. i, to about 3,000 p. s. i.

Pressures in excess of 3,000 p. s. i. may, of course, be employed with satisfactory resutls; however, because of economic considerations, it is generally not advisable to use pressures substantially about 3,000 p. s. i. Thus, by treating the aforesaid feed stream under the abovementioned conditions of temperature and pressure in the presence of steam and carbon dioxide, we are able to realize in a single pass an increaseof at least 35 per cent in the chemicals present in the reaction products over the concentration thereof originally contained in the feed.

It should 'be pointed out that the process of our invention can be employed in a wide variety of feed streams containing chemicals and olefins and is particularly useful where a substantially olefin-free mixture of oxygenated organic chemicals is the desired end product. Mixerally desirable to employ a substantial molar excess of steam and carbon dioxide based on the quantity of olefins present. The minimum molarexcess of steam and carbon dioxide that normally should be employed to convert at least a portion of theolefins to chemicals under the conditions taught herein are set forth in the table "below. This table demonstrates the fact that as the concentration of olefinsin the feed is decreased,

- ture being treated. .mixture containing 90 percent olefins and 10 the minimum molar excess of steam and carbon dioxide required to eifect a conversion of olefins to chemicals should be increased. Part I of the table shows the minimum molar excess of steam and carbon dioxide necessary to obtain a conversion of olefins to chemicals when a feed consisting of 90 per cent olefins is used, while Part II of the table shows the increased concenvtrations of steam and carbon dioxide required to obtain a conversion of substantially equal magnitude of olefins to chemicals when a feed is employed containing 25 per cent olefins and 75 per cent chemicals.

TABLE I Minimum COzzHzOzolefins molar ratio required to convert olefins to chemicals Part I Part II Temp. Pressure F. (p. s. i. g.)

O; H20 Olefins 002 H2O Olefins The table appearing below shows minimum preferred molar ratios of carbon dioxide to steam to olefins necessary to obtain a conversion of at least 30 per cent of olefins to chemicals. The data appearing in Part I of the table are concerned with a feed containing 90 per cent olefins and 10 per cent chemicals While Part II deals with a feed having 25 per cent olefins and 75 per cent chemicals.

TABLE II Preferred CO2:H2O:0lefins molar ratio required to convert olefins to chemicals Part I Part II Temp., Pressure F. (p. s. i. g.)

001 H2O Olefins 002 H2O Olefins From the information shown in the above tables, it may be seen that with increasing temperatures and at constant pressures the required concentration of carbon dioxide increases but slightly; however, under the same conditions, the quantity of water necessary to bring about a conversion of the olefins is substantially increased, thus indicating that the desired reaction is not favored by high temperatures. Increasing pressures at the same temperature show that less of both carbon dioxide and water are required as the pressure is increased, indicating that high pressures favor the desired reaction. Funther examination of the above data shows the be havior of carbon dioxide in the involved reaction is essentially the same as the action of water therein. The quantity of carbon dioxiderequired increases markedly with increasing temperatures and at constant pressure,

'while' increasing pressures at constant temperature are shown to favor the desired reaction by requiring less carbon dioxide.

Also, as previously indicated, at given temperatures and pressures, the minimum quantity of carbon dioxide and steam required to convert olefins to chemicals is dependent upon the concentration of olefins in the mix- Thus, it will be observed that with a per cent 4 chemicals, as shown in Table I, a minimum ratio of carbon dioxide to steam of 0.05:0.04 is required at 400 F. and 1,000 pounds of pressure, while with a mixture containing per cent chemicals and 25 per cent olefins, the minimum carbon dioxide to steam ratio is 0.5:3.0 at the same conditions of temperature and pressure.

The catalyst employed in effecting our invention may be any of those that have previously been shown to be capable of promoting hydrocarbon synthesis by means of the reduction of carbon monoxide with hydrogen, such as, for example, cobalt, nickel, ruthenium and iron. In fluidized bed operations, the catalyst used is preferably employed in a state and under conditions such that the density of the catalyst bed ranges from about 65 to about lbs/cu. ft. with nonterrous catalysts and preferably 85 to lbs/cu. ft. in the case of iron. While, as previously indicated, any of several types of known hydrocarbon synthesis catalysts may be employed in the process of our invention, we generally prefer to use a catalyst commonly designated as mill scale which is described and claimed in U. S. Patent 2,485,945 to S. W. Walker. This catalyst is prepared by reducing the oxide scale or layer obtained by rolling iron or various alloys thereof at elevated temperatures, for example, in the range of 1,000 to 1,300 C. Microscopic examination of the scale or oxide layer thus obtained when ground to a fineness of 325 mesh indicates that it still retains its characteristic plate-like structure. The catalyst is maintained in a fluidized state under the reaction conditions employed by introducing the hydrocarbon feed mixture in vaporous form at a linear velocity of between 0.1 and 2.0 ft. per second. The concentration of catalyst employed in the liquid phase process may vary widely and in general will be determined by the activity of the catalyst used. Thus, for example, with iron type synthesis catalyst, we generally prefer to use a concentration of about 1 lb. of catalyst for each 0.2 to 0.5 mol. of olefins in the feed mixture.

While the process of our invention referred to above and more specifically described below is disclosed generally in terms of vapor phase operation, it is to be strictly understood that We do not limit ourselves to such operating conditions inasmuch as batch or continuous liquid phase operations may be advantageously employed with various combinations of feed mixtures, catalysts, reaction temperatures and pressures. Also in carrying out our invention, the vapor phase conversion of olefins to oxygenated chemicals may, if desired, be eflected in reactors having fixed instead of fluidized catalyst beds.

The process of our invention may be further illustrated by means of the following specific example.

Example An organic layer or stream containing approximately atoms, 5 weight percent saturated hydrocarbons of essentially the same carbon content and about 20 weight per cent of oil-soluble oxygenated organic compounds, i. e., aldehydes, ketones, alcohols and acids, was vaporized by introducing such stream into a gas fired preheater, and the resulting vapors mixed with steam and carbon dioxide after which the mixture was introduced into a conventional hydrocarbon synthesis type reactor at a pressure of about 400 p. s. i. and at a temperature of about 500 F. Water (steam) and the aforesaid organic layer were introduced into the reactor in equivalent amounts (by weight), while carbon dioxide was added in a ratio of about 40 parts (by Weight) per part of steam plus organic layer. This reaction mixture was brought into contact with a fluidized alkali promoted mill scale catalyst. The catalyst was maintained in a dense turbulent state by introducing the reaction mixture at a linear velocity of aboutl ft. per second. The space velocity employed was about 0.075 lb. of feed per 1b. of catalyst however, this figure generally may vary from about 0.03

Alcohols, Carbonyls, Acids, Mols/4 Hrs. Mols/4 Hrs. Mols/4 Total Hrs.

ii'l 2 2 47 0 04 l Water 0.0 0.0 0.0 i 4 51 Products:

Oil 2.08 2.28 0.44 6 09 Water 0.26 0. 23 0.80

It may be seen that a very substantial increase in chemicals can be realized with a once-through operation under the conditions employed in the foregoing example, and that the process of our invention may be readily applied to continuous and cyclic procedures for the conversion of olefins, present in such feed streams, to products of greater value.

It will be apparent to those skilled in the art that numerous modifications in the methods of processing, synthesis conditions, etc., may be employed without departing from the scope of our invention. Thus, while the present invention is particularly useful for the purpose of converting minor quantities of olefins to chemicals in chemical-containing feed streams of the type described, it is applicable also to a wide variety of streams containing higher concentrations of olefins wherein it is desired to convert such olefins into more valuable organic compounds.

The term chemicals as used herein is intended to designate the various types of oxygenated organic compounds that can be produced by the oxidation of olefins and includes compounds such as esters, aldehydes, ketones and alcohols.

What we claim is:

1. In a process for purifying a mixture of oil-soluble oxygenated organic chemicals selected from the group consisting of alcohols, ketones, carboxylic acids and aldehydes contaminated with an olefin having approximately the same boiling point as at least one of said chemicals, the step which comprises subjecting said mixture to the action of carbon dioxide and steam in the presence of an active hydrocarbon synthesis catalyst to convert said olefin into oxygenated organic chemicals having essentially the same carbon contact as the chemicals present in the original mixture to be purified, wherein the minimum ratio of carbon dioxide to steam to olefin ranges from 0.10:0.5 1.0 to 0.10:1.0:1.0 at 200 p. s. i. g. at temperatures of from about 300 to about 500 F. to 0.02:0.20:1.0 to 0.02:1.20:1.0 at 3,000 p. s. i. g. at temperatures of from about 300 to about 700 F.

2. The process of claim 1 in which the minimum molar ratio of carbon dioxide to steam to olefin ranges from 0.10:0.13:l.0 to 0.10:0.20:1.0 at 200 p. s. i. g. and at temperatures of from about 300 to 500 F. to 0.02:0.01:1.0 to 0.02:0.06:1.0 at 3,000 p. s. i. g. at temperatures of from about 300 to about 700 F.

3. The process of claim 1 in which the minimum ratio of carbon dioxide to steam to olefin ranges from 0.05:0.03:1 to 0.05:0.04z1 at 1,000 p. s. i. g. and at temperatures of from about 300 to about 400 F. to 0.1:1.2:1.0 to 0.1:2.0:1.0 at 3,000 p. s. i. g. at temperatures of from about 300 to 700 F.

4. The process of claim 1 in which the catalyst employed is an active iron hydrocarbon synthesis catalyst.

5. The process of claim 1 in which the catalyst is employed in the form of a fluidized bed.

6. The process of claim in which the catalyst is an active iron hydrocarbon synthesis catalyst.

7. In a process for purifying a mixture of oil-soluble oxygenated organic chemicals selected from the group consisting of alcohols, ketones, carboxylic acids and aldehydes contaminated with olefins having approximately the same boiling points as at least some of said chemicals wherein said mixture contains at least about per cent olefins and not more than. about 10 per cent of said chemicals and aldehydes, the step which comprises subjecting said mixture to the action of carbon dioxide and steam in the presence of an active hydrocarbon synthesis catalyst to convert said olefins into oxygenated organic chemicals having essentially the same carbon content as the chemicals present in the original mixture to be purified, wherein the minimum ratio of carbon dioxide to steam to olefins ranges from 0.10:0.5:1.0 to 0.10:1.0:1.0 at 200 p. s. i. g. at temperatures of from about 300 to about 500 F. to 0.02:0.20:1.0 to 0.02:1.20:1.0 at 3,000 p. s. i. g. at temperatures of from about 300 to about 700 F.

8. The process of claim 7 in which the minimum carbon dioxide to steam to olefin ratio ranges from 0.6:10.0:1.0 to 0.6:15.0:1.0 at 200 p. s. i. g. at temperatures of from about 300 to about 500 F. to 0.1:1.2:1.0 to 0.1:2.0:1.0 at 3,000 p. s. i. g. at temperatures of from about 300 to about 700 F.

9. The process of claim 7 in which the catalyst is an active iron hydrocarbon synthesis catalyst employed in the form of a fluidized bed.

10. In a process for purifying a mixture of oil-soluble oxygenated organic chemicals selected from the group consisting of alcohols, ketones, carboxylic acids and aldehydes contaminated with olefins having approximately the same boiling points as at least some of said chemicals where said mixture contains about 10 per cent olefins and not more than about 90 per cent of said chemicals, the step which comprises subjecting said mixture to the action of carbon dioxide and steam in the presence of an active hydrocarbon synthesis catalyst to convert said olefin into oxygenated organic chemicals having essentially the same carbon content as the chemicals present in the original mixture to be purified, wherein the minimum ratio of carbon dioxide to steam to olefins ranges from 0.6:10.0:1.0 to 0.6:15.0:1.0 at 200 p. s. i. g. at temperatures of from about 300 to about 500 F. to 0.1:i.2:1.0 to 0.1:2.0:1.0 at 3,000 p. s. i. g. at temperatures of from about 300 to about 700 F.

11. The process of claim 10 in which the catalyst is an active iron hydrocarbon synthesis catalyst employed in the form of a fluidized bed.

12. In a process for purifying a mixture of oil-soluble oxygenated organic chemicals containing atleast one of the class of compounds consisting of esters, alcohols, aldehydes, ketones and carboxylic acids, and which are contaminated with an olefin having from four to twelve carbon atoms, the steps which comprise converting said olefin into oxygenated derivatives thereof corresponding to at least one of the aforesaid classes of said oxygenated organic chemicals by subjecting said mixture to the action of carbon dioxide and steam in the presence of an active hydrocarbon synthesis catalyst to convert said olefin into oxygenated organic chemicals having essentially the same carbon content as the chemicals present in the original mixture to be purified, wherein the minimum ratio of carbon dioxide to steam to olefin ranges from 0.10:0.5:1.0 to 0.6:15.1:1.0 at 200 p. s. i. g. and at temperatures of from about 300 to 500 F. to 0.02:0.20:1.0 to 0.1:2.0:1.0 at 3,000 p. s. i. g. at temperatures of from about 300 to about 700 F., and recovering a mixture having an increased ratio of said oxygenated organic chemicals to olefin.

13. The process of claim 12 wherein the mixture of oil-soluble oxygenated chemicals constitutes the organic layer from the distillate produced by subjecting to fractionation up to a temperature of about -115 C. an extract solution obtained by extracting hydrocarbon syn- 7 thesis oil With an aqueous solution containing a substan- 2,523,686 tially non-surface active salt of a preferentially oil-sol- 2,549,111 uble carboxylic acid. 2,645,655 2,694,735 References Cited in the file of this patent 5 UNITED STATES PATENTS 469,582

2,035,189 Ramage Mar. 24, 1936 8 Engel Sept. 26, 1950 Millendorf et a1 Apr. 17, 1951 Pearce July 14, 1953 Hull et al Nov. 16, 1954 FOREIGN PATENTS France Aug. 4, 1914

Claims (1)

1. IN A PROCESS FOR PURIFYING A MIXTURE OF OIL-SOLUBLE OXYGENATED ORGANIC CHEMICALS SELECTED FROM THE GROUP CONSISTING OF ALCOHOLS, KETONES, CARBOXYLIC ACIDS AND ALDEHYDES CONTAMINATED WITH AN OLEFIN HAVING APPROXIMATELY THE SAME BOILING POINT AS AT LEAST ONE OF SAID CHEMICALS, THE STEP WHICH COMPRISES SUBJECTING SAID MIXTURE TO THE ACTION OF CARBON DIOXIDE AND STEAM IN THE PRESENCE OF AN ACTIVE HYDROCARBON SYNTHESIS CATALYST TO CONVERT SAID OLEFIN INTO OXYGENATED ORGANIC CHEMICALS HAVING ESSENTIALLY THE SAME CARBON CONTACT AS THE CHEMICALS PRESENT IN THE ORIGINAL MIXTURE TO BE PURIFIED, WHEREIN THE MINIMUM RATIO OF CARBON DIOXIDE TO STEAM TO OLEFIN RANGES FROM 0.10:0.5:1.0 TO 0.10:1.0:1.0 AT 200 P.S.I.G. AT TEMPERATURES OF FROM ABOUT 300* TO ABOUT 500*F. TO 0.02:0.20:1.0 TO 0.20:1.20:1.0 AT 3,000 P.S.I.G. AT TEMPERATURES OF FROM ABOUT 300* TO ABOUT 700*F.