US2575718A

US2575718A - Method of producing polyoleftnic

Info

Publication number: US2575718A
Authority: US
Publication date: 1951-11-20
Anticipated expiration: 1968-11-20

Description

R. J. LEE ETAL Filed April 22, 1948 Nov. 20, 1951 METHOD 0F PRODUCING POLYOLEFINIC HYDROCARBON DRYING OILS Patented Nev. zo, 1951 UNITED STATES PATENT oFFlcE METHOD OF PRODUCING POLYOLEFINIC HYDROCARBON DRYING OILS Robert J. Lee, La Marque, and Pat S. Brennan,

Dickinson, Tex., assignors to Pan American Reinng Corporation, Texas City, Tex., a corporation of Delaware Application April 22, 1948, Serial No. 22.546

3 Claims.

This invention relates to the production of drying oils and other oleflnic hydrocarbons by processing high boiling non-aromatic hydrocarbons with HF and it pertains more particularly to novel polyolen compositions per se and to improved methods and means for obtaining maximum yields of such compositions from charging stocks comprising high boiling paraflins, olens and/or naphthenes such, for example, as dearomatized gas oil.

It is known that drying oils can be produced by hydrolyzing hydrocarbon complexes produced in the treating of various hydrocarbons with such compositions as sulfuric acid, aluminum chloride and hydrogen iiuoride. Heretofore such processes have lacked commercial feasibility for many reasons; for example, some complexes yield oils of relatively low unsaturation, high specific gravity, undesirable boiling range, and/ or other properties which make them unsatisfactory for commercial utilization. An object of this invention is to provide a method and means for producing drying oils of remarkably high unsaturation, containing for example about 4 or more double bonds per molecule, a large portion of which double bonds are in conjugated positions. A further object is to produce polyolens of lower specific gravity for a given boiling range than that exhibited by prior drying oils produced from hydrocarbon charging stocks. A further object is to provide a new type of synthetic hydrocarbon drying oil which is light in color and which radically diiers from any synthetic drying oils of petroleum origin which have heretofore been commercially available. An important object is to avoid or at least to minimize degradation, cracking, polymerization, saturation or other undesirable reactions in the recovery of the drying oil from HF complex material.

A further object of the invention is to provide a process for producing drying oils from a relatively low grade charging stock such as gas oil. A further object is to provide operating conditions for drying oil production which will produce maximum yields of drying oils of desired characteristics while at the same time producing valuable by-product materials. Another object is to provide a relatively simple and inexpensive process for converting hydrocarbons which are higher boiling than gasoline into valuable polyolenic hydrocarbons, substantially saturated hydrocarbons of the motor fuel boiling range and branched chain saturated hydrocarbons such as isobutane. Other objects will be apparent as the detailed description of the invention proceeds.

In practicing the invention a preferred charging stock is a gas oil which has been dearomatized by treatment with concentrated sulfuric acid. Many charging stock materials such, for example, as olen polymers, alkylates, and hydrocarbon fractions produced by carbon monoxidehydrogen synthesis may contain no appreciable amounts of aromatic hydrocarbons and hence may require no dearomatization step. Relatively pure paraflinic hydrocarbons such as cetane and parailiin waxes may be employed but they give a less desirable product distribution and they are not as commercially attractive as the less valuable gas oils. The dearomatization may of course be effected by other means than treatment with sulfuric acid; the aromatics may be removed by use of known selective solvents but for best re-l sults it is important that the aromatic content of the charge be substantially eliminated. The aromatic content should not exceed about 5%. and preferably should be less than about 1%.

The HF treatment of the dearomatized gas oil or other charging stock can be effected at a temperature in the range of about 250 to 450 F., preferably about 300 to 350 F. under a pressure suiicient to maintain liquid phase conditions and with a time of contact which may range from a few minutes to several hours depending upon temperature and intimacy of said contact, excellent results having been obtained with contact times of the order of about 5 to 30, e. g. about 20 minutes. The HF-to-oil ratio may vary from about 0.1:1 to about 5:1 or more but is preferably in the range of about 1:1 to 2:1.

The products of the HF treatment are preferably cooled and separated into an HF phas'e containing soluble unsaturated hydrocarbons and an insoluble oil phase which consists essentially of saturated hydrocarbons and contains only a small amount of dissolved HF. The oil phase is stripped for removing HF and fractionated to produce motor fuel along with lighter and heavier fractions.

The HF phase separated from the product of the treating step is subjected to a partial stripping operation to remove most of the HF from an HF-polyolefinic hydrocarbon complex without decomposing or degrading said complex. This stripping can usually be effected at temperatures below about 300 F., and in most cases in the range of about to 150 F.; and it may be accomplished by the use of an inert'stripping gas and/or by heating. It is important that at least one and preferably one and one-half to two molecules of HF should be left in the stripped residue for each double bond present in the oil components thereof; for practical purposes this means that the stripped residue should contain at least about 30% HF and preferably about 35 to 50% HF by weight. Attempts to recover all of the HF by vacuum distillation or stripping ammonia or an aqueous caustic solution. Usu' noting when the interface :between ,the acid and the hydrocarbon phases had been reached. i The ally cooling is required in this operation to avoid I loss of light ends and to absorb the heat of neutralization. The neutralization may be effected with aqueous ammonia. using adequate cooling so that side reactions are substantially eliminated and neutralization takes piace very rapidly without any substantial increase in temperature. The treated complex is thus substantially freed from HF. i. e. it contains less than about 0.1% HF by weight.

The stripped complex may be neutralized by intimate contact with an aqueous caustic solution. Strong caustic solutions may be employed at elevated temperatures (e. g. U-200 C.) to neutralize the HF, effect isomerization, and give increased yields of a product in which the double bonds are in conjugated position. The neutralized product may then be distilled with inert gas, steam or under vacuum to remove low boiling components therefrom and to produce drying oils either as overhead or as undistilled fractions of desired molecular weight. The drying oils thus produced have remarkably high iodine numbers which usually range from about 450 to 550, from which it may be calculated that they contain 4 to 6 double bonds per molecule (one-third to one-half of which are in conjugated position) and they have remarkably good color. A typical drying oil may have an average molecular weight of about v225, an iodine number of about 475, an ASTM color of about 4, and a maleic anhydride value of about 350. In this connection, iodine number is understood to mean centigrams of iodine per gram of sample as determined by the Wijs iodine monochloride procedure using 1/2 hour reaction time and 200% excess reagent. Maleic anhydride value represents the milligrams of maleie anhydride which will react with one gram of sample (also referred to as the diene number) and is a measure of the amount of conjugated olefinic double bonds in the samples.

The invention will be more clearly understood from the following detailed description read in coniunction with the accompanying drawings in which:

Figure l is a schematic flow diagram illustrating a commercial plant for practicing the invention, and

Figure 2 is a neutralization system utilizable in the system of Figure l.

Before describing the operation illustrated in the drawings, data will be presented to show the importance and signiilcance of operating conditions. The optimum charging stock appears to be a dearomatized gas oil. The following table sets forth data obtained by treating various charging stocks with a 2:1 HF/oil weight ratio at a temperature of about 330 F. for a contact time of about minutes in an autoclave provided with a motor-driven propellor-type agitator. In these runs, at the end of the reaction period, the reaction mixture was allowed to settle while cooling to room temperature. The lower HF phase was then withdrawn from the bomb through a Saran tube into a neutralizing mixture of aqueous ammonia and cracked ice. The transparent Saran tubing served as a means of ammonium-fluoride solution was allowed to settle and the poly-olefinic oil was decanted from the solution. 'Ihe hydrocarbon phase from the reactor was neutralized in a similar fashion and collected separately.`

Efecto! lcharac stocks I Cu Cu Cu Cle Charge Stock Branched Normal Brenched Normal Oleiin 1 Olefin i Parailln 5 Paraln l Vol. Per Cent Conversion 93-100 (100) 26. 1 43. 3 Yield of Unsatd Oil 38.2 28. 8 8. 9 l5. 2 Iodine N0. 440 467 503 475 Refractive Index. 1.526 l. 507 1. 502 1. 498 Molecular Weight. 212 205 213 Cl Dearomatized Ges Oils Branched Charge Stock 2-2-4gillx- N h me y a pentane Param!" thexgice l Vol. Per Cent Conversion 95. 7 58.7 65 Yield of Unsatd Oil 19.5 24.3 22.3 Iodine No 506 475 481 Refractive Index. l. 4910 l. 517 l. 503 Molecular Weight. 225 201-229 1Tetra isobutylene fraction recovered from isobutylene polymer produced bg HzSO4 polymerization.

2 Normalexadecene. 95% purity.

S Product from completo hydrogenation of (l).

i Catane, 93% purity.

l East. Texas gas oil MON-650 F. boiling range), dearomatized by exhaustive sulfuric acid treating to a reduced aromatic content of less *hun 1%.

6 Hastings gas oil (400-650" F. boiling rarge), dearomatized by exhausrive sulfuric acid treating to a reduced aromatic content of less than 1%.

When consideration is given to percent conversion, unsaturated oil yield in conversion products, and iodine number of unsaturated oil, it will be noted that the dearomatized gas oils provide a very good charging stock particularly when their cost is compared with that of other charging stocks. The effect of dearomatization is shown by comparative tests on a virgin East Texas gas oil containing about 17% aromatics as compared with the same gas oil after dearomatization by repeated treatment with sulfuric acid. Employing the same treating conditions (2:1 HF-oil Weight ratio, 350 F. and 20 minutes contact time) the following comparative data were obtained:

- Dearoma- Charge Stock Vugcas tized Gas Oil Aromatics 17. 0 1 Volume Per Cent Conversion 40. 5 59 Yields (Vol. Per Cent on CHG) Dry Ci .4 1. 2 Isobutane 4. 3 12. 0 Normal Butanc .1 l. 0 Butenes .0 .1 Pentanes 2. 2 6. 5 Pentenes. 4 1. 0 a-205 15. l l2. 9

Total 22. 5 34. 7

Recycle gas oil 59. 5 40. 7 HF Soluble Product:

elow 205 F 1.9 4. O Ges Oil Range 5. 6 1l. 2 Eeavier than Gas Oil 9. 2 8. 1

Total 16. 7 23. 3

Properties of HF Soluble Oil:

Iodine Number (Wijs, 56 hr.) 297 475 Specific Gravity (60 E.) 9786 .9059 Refractive Index (71u25) 1. 505 Gardner Viscosity at 25 C 1 A-4 l Approximately 6 centistokes.

The effect of aromatics on the nature and'extent of the conversion is strikingly illustrated in the above table. With respect to the HF-soluble For comparison, properties of the HF-solubletreating of. de-

product obtained from y the HF aromatized gas il are as follows:

v Estimated v Vol. Per o C Temp. Ovhd. Iodine Sp. Gr. v Mol Cut No. Cent n Ovh'd at mm. Temp. At Numnu At wt Chg.` Hg 760mm., ber 25 C.

` v GASOLINE RANGE MATERIAL GAS OIL RANGE MATERIAL HEAVIER THAN G. O. RANGE MATERIAL 6 11. 3 185 1. 2 720 l 445 1. 5260 9508 279 Bottoms 23. 5 348 379 Total Material 475 9059 l Gardner viscosity at C.=A (ca. 50 centistokes or 230 SSU at 25 0.). 1 Gardner viscosity at 25 C.-L (ca. 800 centistokes or 1460 SSU at 25 0.).

products,r the pronounced difference in proportions and particularly in degree of unsaturation is shown by the following comparative data on respective HF-soluble products after neutralization toremovenal traces of HF and after removing C5 and lighter hydrocarbons.

HF-soluble products from A more detailed analysis of the HB1-soluble product from the treating of virgin East Texas 5 gas oil is as follows:

From the above data it appears that the average hydrocarbon in the HF-soluble product may be pictured as an unsaturated hydrocarbon containing about 15 .or more carbon atoms and about 4 or more double bonds, about 2 of which are in conjugated relationship.` The high unsaturation begins with the product hydrocarbons having about 10 carbon atoms per molecule, these containing upwards of 3 double bonds per molecule. The gas oil boiling range material may consist of hydrocarbons averaging about 12 to 20 carbon atoms per molecule and here the number of double bonds is about 4 to 5 per molecule. The higher boiling material of longer chain lengths may have from 5 to 6 double bonds per molecule. The product produced from dearomatized gas oil exhibit almost twice the unsaturation exhibited by products from the original gas oil containing about 17% aromatics. The relative freedom from aromatics exhibited by the products from dearomatized gas oil might be expected but the remarkably high unsaturation and low specific gravity of the V l P T Ebgnllllted I d' S G o er emp. v o me p. r. Cut No. Cent 0 Ocyd" at mm. Temp. At Numun At Chg. Hg 760r1`m.. ber 257 C.

GASOLINE RANGE MATERIAL Degrees 765 158 765 212 48 l. 4090 7258 213311 GAS OIL RANGE MATERIAL HEAVIER THAN G. O. RANGE MATE RIAL 16. 7 185 1 725 237 1. 5550 9716 230 10. 3 217 1 273 1. 5783 9976 253 Bottoms 27. 9 181 1.0928 46T Total Material 297 .9632

. alrna'nel products obtained from dearomatized gas oil were l verysurprising.

In addition to the above properties of HF-soluble products produced from dearomatized gas oil it is noteworthy that such products possess a high maleic anhydride value (M. A. V.). For example, cut No. 2 had an M. A. V. of 625 which with its iodine number of 613, mol. weight of 132, and refractive index of 1.4665 indicates a mixture of tri and tetra oleflns (3.2 double bonds per mol) which are largely conjugated in structure; i. e.

.at least 85% of the molecules have one pair of conjugated double bonds. This was qualitatively confirmed by ultra violet spectrophotometric observation. A blend of cuts 4, and 6 showed an M. A. V. of 302, an iodine number of 475, a refractive index of 1.517 and a molecular weight of 250; this indicates that the material is composed of polyolefins containing approximately 4 or more double bonds per molecule and that about '75 to 80% of the material contains one pair of double bonds in conjugation. This is a very unusual combination of properties.

The colors of thev vacuum distillate fractions were good varying l-11/ for the lower boiling components to 31/2-5 ASTM for the high boiling products.

For use in the drying oil and/or resin field. cuts 4, 5 and 6 (which represent approximately 43% of the total HF-soluble product) possess the requisite low volatility and adequate body (viscosity) to meet commercial requirements. Each of these fractions air-dry readily and a compositeIl sample produced a slightly less brittle film than a corresponding polymer drying oil produced by contacting unrefined cracked gasoline vapors with an absorbent clay under conditions for removing and polymerizing diolefins. Such clay polymer is believed to represent the best drying oils heretofore obtainable from petroleum, but the striking difference between such drying oil and the drying oil of this invention is shown by the following tabulated Properties:

Drying oil from HF Drying Oil treating of from dearom. Clay Polymer gas oil l Boiling Range, C. at i mm. Bg 10G-185 104-225 Refractive Index at 25 C 1. 5178 l. 5365 Speciiic Dispersion (nl, nc) 150 170 Specific Gravity :11.25 C 0. 0274 0. 969 Iodine Number 439 189 M. A. 302 27 Per Cent Conjugation (from M A V. 77 7 Approximate Mol` Weight 250 290 Viscosity at 100 F.:

Centstokes 17. 28 41.7 Saybolt Universal Sec 86 194 olor:

Gardner i3 l5 ASTM 4+ 5 Drying Time:

(Set to touch),2 Hrs l%-2% it-2% (Tack-free), Hrs 6-8 l Composite of cuts 4, 5 and 6. l 1 With 0.5% lead naphthenate and 0.05 cobalt naphthcnate drlers.

Referring now to the effect of process variables in producing the polyolen or drying oil materials, the most important are HF/oil ratio, contact time (assuming intimate mixing) and temperature. As the HF/oil weight ratio is increased from about .25:1 to about 3:1 there is a gradual increase in product iodine number and a substantial increase in yield. HF/oil ratios below about 1:1 are usually undesirable not only because of limited yield and lower product unsaturation but because of limited physical capacity of the available HF to dissolve the polyolefinic material. The preferred HF/oil ratio'is about 1:1 to 2:1 and it is usually uneconomical to employ a greater ratio vthan 5:1. The properties of the drying oil are not substantially affected by changes in the HF/oil ratio.

The required contact time is dependent on temperature and intimacy of contact; higher temperatures make possible the use of shorter contact times. With an HF/oil ratio of 2 (i. e. 2:1) and a 20 minute contact time, a yield of about 12% is obtained at 265 F. (iodine number 461) while a yield of about 22% is obtained at about 300 F. (iodine number about 510). Adequate conversion at lower temperatures may require a contact time of an hour or more. At higher temperatures. lower HF/oil ratios may be 'employed advantageously. For example. in a pilot plant run, employing continuous flow type operation at 355 F. and 1:1 HF/oil ratio and 6 to 8 minute contact time, a yield of 12.5 wt. per cent of 474 iodine number oil was obtained. At

ltemperatures of the order of 400 F. the contact peratures such contacting Ytime is in the range of about 5 to 30 minutes. The preferred temperature is in the range of about 300 to 400 F. The iodine number has been observed to decrease with excessively long contact times, said decrease being accompanied by an increase in molecular weight and specific gravity.

Referring now to the drawing, a dearomatized gas oil (or other substantially nonaromatic high boiling hydrocarbon charge) is introduced by line l0 through heater il to reactor I2 together with HF introduced through line I3, about 2 parts by weight of HF in this case being introduced per part of oil charge. The reactor may be a batch type or continuous reactor of any known type which will give sufficient intimacy of contact for the required period of tim-aand it is illustrated as-a cylindrical vessel provided with a mechanical stirre'r I4 driven by motor I5. In the reactor, conversion is effected at a temperature of about 330 F. with a contact time of about 20 minutes under a pressure suicient to maintain liquid phase conditions, e. g. about 800 to 1500 p. s. i. The charge should of course be dry when it is introduced into the system and conventional drying towers may be employed when necessary. The reactor and other elements must of course; be fabricated from or lined with metals, alloys or compositions which are resistant to hydrogen fluoride and may for example be made of Monel or Monelclad. The reactor may consist of a tank provided with a pump-circulated emulsion stream such as employed in conventional sulfuric acid alkylation operations. l Since no invention is claimed in the reactor per se it requires no further description.

The reaction mixture Vis passed through a cooler i6 before being introduced from line l1 to product separator I8. The separator or settler i8 Amay be operated at ,substantially reaction preswhich is preferably operated at a temperature obtainable with ordinary condenser water. Any condensed hydrocarbons separate out as an upper layer and they may flow over baille 26 and be withdrawn through line 21. A portion of such material may be employed as a stripping gas in stripper 2| and/or in the complex stripper which will he hereinafter described. The net production of the condensed hydrocarbons may be passed through a bauxite tower or otherwise treated to remove HF and/or combined fluorides. Similarly the gas vented from the separator through line 28 may be freed of HF and utilized in any conventional manner. 'Ihe acid layer is Withdrawn through line 29 to HF storage tank 36 from which it is supplied to line I3 by pump 3|.

The stripped saturated oil leaves the base of stripper 2| through line 32 and is then fractionated in a conventional system diagrammatically illustrated by tower 33, the light hydrocarbons such as gasoline being taken overhead through line 34 and the heavier hydrocarbons being Withdrawn through line 35. Conventional bauxite treating may be used to remove any residual fluorides.

The HF phasey from settler IB which Amay in this case consist of about to 20 weight percent of unsaturated hydrocarbon material and 80 to 90% by weight hydrogen fluoride is withdrawn through line 36 to HF-complex stripper 31 to which a stripping gas (e. g. from line 21) may be introduced through line 38. Heating means 39 may be employed at the base of this stripper, which operates at temperatures of the order of 12S-150 F. The stripping in tower 31 should be suicient to remove the uncombined HF but to leave at least 1 molecule and preferably 11/2 to 2 molecules HF per double bond in the hydrocarbon components contained in the HF solution. In other words. the HF content of the introduced mixture should be reduced to about 35 to 50% by weight but should not be reduced to less than about 30% by weight. stripped product containing 35 weight percent HF will give an ultimate drying oil of about 450 to 500 iodine number, but if more HF is removed from the material the iodine number of the resulting product gets lower and lower. When stripping is continued to HF content the product iodine number is only slightly above 400. When stripping is continued to 10% HF content, the product iodine number is only about 340. When stripping is continued to .5% HF content, the product iodine number is less than 200. An important feature therefore is to remove the bulk of the HF in this stripping operation without decomposing what is apparently an HF- unsaturated oil complex and to accomplish this purpose, the stripping temperature and pressure should be controlled so that the material leaving the base of the stripper will contain at least 30% and preferably 40 to 50% of HF.

`The HF and stripping gas which leaves the top of stripper 31 through line 40 may be combined with the overhead from stripper 2l a part of the overhead may be introduced through branched line 4I into the upper part of stripper 2i and another part may be introduced directly to line 23.

The HF-unsaturated oil complex from the base of stripper 31 may be introduced through cooler 42 and line 43 into a neutralizing system 44 which is shown as a continuous countercurrent tower in Figure 1 and as a multiple batch system in Figure 2. Neutralization is effected by Thus a 10 means of an aqueous neutralizing material or reagent such as ammonia, sodium hydroxide, potassium hydroxide, lime, etc., preferably by aqueous ammonia solution containing from 10 to 20% ammonia. The neutralizing material is introduced through line 45 in suflicient amount to at least neutralize the HF. In the system diagrammatically illustrated in Figure 1, neutralization is effected in a countercurrent tower which may be provided with suitable mixers or contacting surfaces and which may be provided with a series of cooling coils 46, 41 and 48 for temperature control. At the complex inlet end the temperature should be relatively low, e. g. about 30 to F. At the upper end of the tower where the complex has been substantially denuded of combined HF, a higher neutralization temperature of the order of 60to 150 F. may be employed for removing as much as possible of the combined HF. While the use of a countercurrent system with a temperature gradient as hereinabove described is preferred, it should be understood that the neutralization may be effected at a substantially constant temperature attainable by cooling water, i. e. in the range of 32 to F. or about 85 F. l v

For obtaining the desired intimacy of contact in the neutralizing step it may be desirable to employ one or more stirred vessels operated batchwise as illustrated in Figure 2. In this case complex from line 43 and aqueous ammonia from line 45 are introduced into stirred mixing vessel 44a which is provided with a jacketed cooler 48a. After intimate mixing for a period of 2 to 20 minutes at about 30 to 125 F. the mixture is introduced by line 49 into batch settler 50. After settling for about 20 minutes the aqueous solution is withdrawn from settler 50 through line 43a and the oil layer is introduced into mixer 44h with additional aqueous ammonia. from line 45h. After stirring for another 2 to 20 minutes in this mixer while maintaining a temperature of 50 to F. by cooling jacket 41h the mixture may be introduced by line 49 into settler 50' from which aqueous ammonium fluoride is withdrawn through line 5|b and crude drying oil through line 52.

To remove any final traces of HF the crude drying oil may be contacted with bauxite or it may be further neutralized at elevated temperature (e. g. 10U-200 C.) with caustic solution introduced through line 53 and intimately mixed with the crude drying oil in mixer 54. The mixture then -passes to settler 55 from which the caustic is settled out and withdrawn through line 56, most of the caustic being recycled by pump 51 and a very small amount of spent caustic being Withdrawn through line 58. The amount of caustic employed is not critical but it is preferred to employ about .l to 1 part of concentrated caustic solution since the contacting With-caustic in this final neutralization step serves not only to remove the final traces of HF but also to isomerize the olens and increase the preponderance of conjugated diolen structure.

The neutralized product may then be distilled under subatmospheric pressure (preferably in the range of 1 to 10 mm.) in conventional distillation equipment illustrated by tower 60, the gasoline boiling range materials being taken overhead through line 6l, drying oil distillate being recovered through line 62 and a high boiling polyoleflnic drying oil or resin being withdrawn through line 63. Fractions of any desired boiling ranges may thus be obtained. Atmospheric ilash distillation may be employed where the time at elevated temperatures is minimized. A preferred operation is atmospheric distillation in a first tower to remove the lowestI boiling component followed by vacuum distillation in a second tower i'or separation of one or more drying oll fractions.

The drying oil fractions may be utilized directly as such or as a replacement for linseed oil in varnish oils or resins, ink oils, etc., the hydrocarbon nature of the material imparting to any such formulation considerable resistance to water and caustic materials. The fractions also offer utility in core oils, linoleum formulations, binders for pressed wood and brous material, plywood laminating agents, paper impregnants, and waterproong agents. Their conjugated structure enhances their `reactivity with other unsaturated compounds. They-react with maleic anhydride to form valuable unsaturated dibasic acids or acid anhydrides. 'The -COOH acid groups thus incorporated in the molecule permit esteriiication with various monohydric. dihydric and polyhydric alcohols to give a variety of highly useful oils and resins. Certain fractions, particularly the simpler low boiling fractions, offer advantages :s raw materials in the chemical lndustry. Al-

cohol, acidic groups and the like may be introduced into the molecule bymild oxidation, reaction with halohydrins, nitrogen tetroxide, ketene, sultonation, etc. The highest boiling fractions may find application in core binders, graphite, electrode binders, asphalt coatings, Wood impregnants and the like. A small amount of organically bound fluorine and sulfur may be left in these heavy fractions to impart useful toxic properties. The above are merely illustrative of the many uses to which these new materials may beapplied.

From the above description it will be seen that the objects of the invention have been attained. The invention is not limited, however, to the details hereinabove set forth since many moditlcations of equipment and alternative procedures, conditions and proportions will be apparent from the above description to those skilled in the art.

We claim:

1. The method of obtaining a synthetic drying oil having an average molecular weight of at least about 200, an iodine number in the range of about 400 to 600 and a maleic anhydride value of atleast 250, which method comprises contacting a hydrocarbon charging stock which is substantially free from aromatic hydrocarbons with hydrogen fluoride at a temperature in the range of 250 to 450 F. under a pressure suilicient to maintain liquid phase conditions with an HF to oil ratio in the range of .1:1 to 5:1 and with a contact time in the range of about 5to 30 minutes, cooling the contacted materials and separating said materials into a saturated oil phase Acontaining only a small amount of dissolved HF and an HF phase composed chiey of free HF but containing hydrogen fluoride-hydrocarbon complex in solution, stripping said free HF from the hydrogen iiuoride-hydrocarbon complex in the HF phase at a temperature in the range of about to 300 F. and under suilicient pressure to leave at least about one molecule, but not more than 2 molecules, of HF per double bond in the hydrocarbon component of the complex whereby decomposition of said complex is avoided in the stripping step but substantially all uncombined hydrogen fluoride is removed therefrom, neutralizing the HF complex containing at least about 1 but not more than about 2 molecules of HF per double bond in the hydrocarbon component thereof by contacting said complex with an aqueous alkaline solution at a temperature in the range of 30 to F., separating the resulting hydrocarbon and aqueous phases respectively from each other, treating the hydrocarbon phase. to eliminate residual amounts of HF and distilling under subatmospheric pressure the hydrocarbon phase from which residual HF has been removed.

2. The method of claim 1 wherein the aqueous alkaline solution is an aqueous ammonia solution containing about 10 to 20% ammonia.

3. The method of claim 1 wherein residual HF is removed from the hydrocarbon phase by contacting said phase at a temperature in the range of about 100 to 200 C. with a concentrated caustic solution.

ROBERT J. LEE. PAT S. BRENNAN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,432,505 Burk et al. Dec. 16, 1947 2,435,621 Brooks et al. Feb. 10, 1948 2,436,695 Kuhn Feb. 24, 1948 2,440,459 Bloch Apr. 27, 1948 2,440,477 Johnstone Apr. 27, 1948 2,470,894 Johnstone May 24, 1949 OTHER REFERENCES Kalichevsky et al., Chemical Refining of Petroleum, pages 49-50 (1942).

Claims

1. THE METHOD OF OBTAINING A SYNTHETIC DRYING OIL HAVING AN AVERAGE MOLECULAR WEIGHT OF AT LEAST ABOUT 200, AN IODINE NUMBER IN THE RANGE OF ABOUT 400 TO 600 AND A MALEIC ANHYDRIDE VALUE OF AT LEAST 250, WHICH METHOD COMPRISES CONTACTING A HYDROCARBON CHARGING STOCK WHICH IS SUBSTANTIALLY FREE FROM AROMATIC HYDROCARBONS WITH HYDROGEN FLUORIDE AT A TEMPERATURE IN THE RANGE OF 250* TO 450* F. UNDER A PRESSURE SUFFICIENT TO MAINTAIN LIQUID PHASE CONDITIONS WITH AN HF TO OIL RATIO IN THE RANGE OF .1:1TO 5:1 AND WITH A CONTACT TIME IN THE RANGE OF ABOUT 5 TO 30 MINUTES, COOLING THE CONTACTED MATERIALS AND SEPARATING SAID MATERIALS INTO A SATURATED OIL PHASE CONTAINING ONLY A SMALL AMOUNT OF DISSOLVED HF AND AN HF PHASE COMPOSED CHIEFLY OF FREE HF BUT CONTAINING HYDROGEN FLUORIDE-HYDROCARBON COMPLEX IN SOLUTION, STRIPPING SAID FREE HF FROM THE HYDROGEN FLUORIDE-HYDROCARBON COMPLEX IN THE HF PHASE AT A TEMPERATURE IN THE RANGE OF ABOUT 100 TO 300* F. AND UNDER SUFFICIENT PRESSURE TO LEAVE AT LEAST ABOUT ONE MOLECULE, BUT NOT MORE THAN 2 MOLECULES, OF HF PER DOUBLE BOND IN THE HYROCARBON COMPONENT OF THE COMPLEX IS AVOIDED IN THE STRIPPING TION OF SAID COMPLEX IS AVOIDED IN THE STRIPPING STEP BUT SUBSTANTIALLY ALL UNCOMBINED HYDROGEN FLOURIDE IS REMOVED THEREFROM, NEUTRALIZING THE HF COMPLEX CONTAINING AT LEAST ABOUT 1 BUT NOT MORE THAN ABOUT 2 MOLECULES OF HF PER DOUBLE BOND IN THE HYDROCARBON COMPONENT THEREOF BY CONTACTING SAID COMPLEX WITH AN AQUEOUS ALKALINE SOLUTION AT A TEMPERATURE IN THE RANGE OF 30* TO 150* F., SEPARATING THE RESULTING HYDROCARBON AND AQUEOUS PHASES RESPECTIVELY FROM EACH OTHER, TREATING THE HYDROCARBON PHASE TO ELIMATE RESIDUAL AMOUNTS OF HF AND DISTILLING UNDER SUBATMOSPHERIC PRESSURE THE HYDROCARBON PHASE FROM WHICH RESIDUAL HF HAS BEEN REMOVED.D.