US2796384A - Additive sweetening of hydrocarbon oils with air, a phenylene-diamine and alcoholic alkali followed by a metal naphthenate - Google Patents

Description

June 18, 1957 Filed May 4, 1955 United AStates Patent @dice Y 2,7916 ,3;84 Patented JuneA 1,8, 1957 ADDITIVE SWEETENING F HYDROCARBON UTLS WITH AIR, A PHENYLENE-DIAMINE AND ALCOHOLIC ALKALI FOLLOWED BY A METAL NAPHTHENATE Johan C. D. Oosterhout, James L. Meadows, Gordon H.

Miller, and Frank L. Barger, Port Arthur, Tex., assignors to The Texas Company, New York, N. Y., a corporation of Delaware Application May 4, 1955, Serial No. 505,928

16 Claims. (Cl. 196-29) This invention relates to certain improvements in the additive sweetening of hydrocarbon oils particularly light hydrocarbon oils such as gasoline, naphtha and kerosene.

In the additive sweetening process certain materials are added to the oil streams in the run-down lines, extending from cracking, distilling or fractionating units to tankage, for the purpose of sweetening and stabilizing the hydrocarbon oil without the necessity of using special treating equipment for effecting these objects. The additives effect the sweetening and stabilizing of the hydrocarbon in the tank afferra period of time.

An important object of the present invention is to effect a reduction in the time required for the sweetening reaction so that the contents of the run-down tank can be quickly pumped to storage.

In accordance with the invention the hydrocarbon oil in the presence of air is subjected to contacting with a phenylenediamine or a dialkyl derivative thereof such as an N,N-dialkyl-para-phenylenediamine and with expendable amounts of alcoholic alkali metal hydroxide, such as potassium or sodium hydroxide, and certain organic salts, such as copper and cobalt naphthenates. By expendable amounts of caustic and copper or cobalt salts we refer to very minute quantities the recovery of which may be disregarded.

The additives are introduced into the oil stream flowing to a tank and sweetening is effected with a Very short time of standing in the tank. Frequently the oil in the tank will be found to be sweet as soon as it is full and generally the oil will be sweet within some two or three hours and in any case within about or 6 hours. After the oil is sweet a metal deactivator is added such as salicylalaminoalkane, preferably a polysalicylalpolyaminoalkane such as N,N'-disalicylal1,2-diaminopropane. On account of the presence of the salts of copper or cobalt it is desirable to add a metal deactivator so that the treated oil will not only be sweet and substantially free of mercaptans but will also be stabilized against oxidation and gum formation.

We find that a certain sequence in the addition of the additives must be adhered to in lorder to obtain rapid sweetening. Both copper naphthenate and cobalt naphthenate will react under certain conditions with sodium hydroxide to form copper or cobalt hydroxides. The opportunity for reaction between the copper or cobalt naphthenate and the alkali metal hydroxide must be minimized. The most satisfactory method of preventing or reducing interaction between the caustic and copper or cobalt salts is to add the copper or cobalt naphthenates last in the sequence of the sweetening additives. The order of addition of the other additives is not of such critical nature; thus as to the phenylenediamine and alcoholic caustic either may be added first or they may be added at the same point in the oil stream. The 4air may be introduced at any convenient'point in the stream. As stated after the sweetening reaction is completed the metal deactivator is added.

The alkali metal hydroxide is 'used in alcoholic solu- 2 tion. The aqueous solution when used in expendable amounts in the combination of additives employeddoes not yield a sufficiently rapid rate ofrsweetening. It appears that the presence of, the `alcohol may change the mechanism of the sweetening reaction. Thus when usingy a solution of sodium hydroxide Vin methyl alcohol it is possible that some sodium methylate is formed which is sufficiently oil soluble or settles from the oil so slowly that increased contacting with the caustic is afforded which increases the rate of sweetening. The hydroxide may be used in solution with various alcohols such as ethyl, methyl and isopropyl. Methyl alcohol is the most satisfactory. The alcoholic hydroxide is used in minute quantities not exceeding about 0.05 percent by volume of the hydrocarbon oil being treated. Proportions of the alcoholic caustic varying from about 0.002 to 0.05 percent have been found adequate to supply the slight alkalinity desirable for sweetenngwith thecombination of additives employed.

The copper naphthenate or cobalt naphthenate or mixtures thereof are added to the oil in minute proportions of the order of about l to 10 pounds of the naphthenate per 1000 barrels of oil being treated.

The air or` oxygen is added in a quantity at least approximating, and preferably exceeding, the theoretical amount required for oxidizing the mercaptans contained in the hydrocarbons. It appears that the presence of the air is the most important factor in the combination influencing the sweetening rate. i Y

As to the phenylenediamine oxidation inhibitor the preferred material is N,Ndisec.-butyl-para-phenylenediamine. This material is marketed under various trade names such as UOP No. 5, Du Pont No. 22 and Tenamene 2. The phenylenediamine is used in minute amounts such as about 5-10 lbs. per 1000 barrels of ol treated.

The combination of the additives mentioned effectually sweetens the oil at faster rates than havebeen possible in prior methods of additive sweetening. The time required for sweetening will not run over about 5 to 6 hours and in some cases it is possible to have the tank sweet as soon as it is full. Furthermore, the invention makes it possible to sweeten stocks containing higher mercaptan sulfur contents than it has been possible previously to sweeten by the additive technique. In view of the addition of the copper or cobalt compounds to the oil it is desirable at the completion of the treating described to add a metal deactivator Such Vas a salicylalaminoalkane, preferably a polysalicylalpolyaminoalkane, such as N,N-disalicylal1,2-diaminopropane. About three parts of the metal deactivator to four parts of the copper naphthenate will give a product of good`initial gum test and good induction period in the oxidation stability test. Y.' In typical operations in accordance with the invention `naphtha stocks were sweetened and stabilized by contacting with copper naphthenate within a range of about- 1 to 10 pounds per 1000 barrels of naphtha, with methyl alcohol solutions of sodium hydroxide having-normalities approximating 4 in quantities of 0.002 to 0.05 percent by volume of the naphtha or 1 to 30 pounds NaOH per 1000 barrels, with N,N'-di-sec.-butyl-para-phenylenediamine in dosages varying from 7 to 11.5 pounds per 1000 barrels and with air rates furnishing somewhat greater For the purpose of more fully describing the'inventionA 3 reference is had to the accompanying drawing or flow diagram showing a preferred embodiment of the invention.

The drawing shows a pipe manifold connected to a run-down tank 11. The oil to be additive sweetened is directed through a line 12 to the manifold 10 from a cracking, distilling or fractionating unit or other source. An oriiice 13 is provided in the manifold so as to eiTect an increase in velocity and turbulence and improve the intimacy of contacting of the ingredients in the latter portion of the manifold just before the mixture enters the tank 11. The phenylenediamine inhibitor is admitted to the manifold by a pipe 14 and the alcholic caustic enters through a line 15. Air is admitted by a line 16 and the copper or cobalt naphthenate is introduced by a pipe 17. The sweetened produ-ct is withdrawn through a line 18 into which the metal deactivator is injected by a pipe 19.

In a series of runs made with the apparatus shown in the drawing the manifold 10 consisted of a 6 pipe 10' long. N,Ndi-sec.butylpara-phenylenediamine was admitted as a solution in light naphtha (48% phenylenediamine and 52% light naphtha). Copper naphthenate was used in the form of an 8% copper liquid and was charged in solution with naphtha. The alcoholic caustic admitted was composed of anhydrous methyl alcohol and dry flake caustic (76% NazO). The normality varied from 3.8 to 4.2. The charging stock was light naphtha from a fluid catalyst cracking unit. It was taken directly from the distillate accumulator on the unit and charged to the manifold pipe 10 and thence to the run down tank 0 The accompanying table presents data obtained in certain of these runs. The table shows the average residence time in hours in the tank required for the naphtha to become sweet, the figures including the actual time of standing after the tank was full plus one-half the time required to till the tank. The table shows the quantity of the phenylenediamine inhibitor in pounds per 1000 barrels of naphtha charge, the volume percent of caustic based on the naphtha charge, the type of caustic, the pounds of copper naphthenate per thousand barrels of naphtha charge, the air rate in pounds per hour and the percentage of air based on the theoretical quantity of air required for oxidizing the mercaptan sulfur content of the naphtha. In the last column the grams per liter of mercaptan sulfur based on the naphtha charge is given.

In another series of runs the additives were injected immediately into the line from the distillate receiver on the fluid catalyst cracking unit and a slightly different sequence of addition was used. The phenylenediamine inhibitor and alcoholic caustic were introduced into the line together and then the air and copper naphthenate were injected. The run line from the distillate receiver to the run-down tank was some 1500 feet long giving a time in the line of about four minutes and it was found that this duration of time accompanied with the turbulent iiow in 'the pipe provided opportunity for considerable interaction between the caustic and the copper naphthenate so that the effectiveness of these reactants in accomplishing sweetening was reduced. Improved results were obtained by injecting the copper naphthenate in the line immediately at the entrance to the run-down tank. The naphtha was satisfactorily sweetened and stabilized by using more than the theoretical quantity of air, with phenylenediamine in quantities of about 10 pounds per 1000 barrels of naphtha, with 0.002 volume percent alcoholic caustic and with copper naphthenate in amounts of about 3 pounds per 1000 barrels and with the addition of N,Ndisalicylal1,2-diaminopropane in amounts of about 2% pounds per 1000 barrels.

A curious phenomenon in connection with the practice of the invention is the apparent seeding effect of a sweet distillate in the bottom of the settling tank is promoting the sweetening of the distillate admitted to the tank. Thus when the distillate being treated is directe-d into a tank which already contains sour tank bottoms, the time for sweetening the entire tank will be longer than if the tank contained some sweet distillate in the rst place. Thus when the tank bottoms are sweet and more than 100% of the theoretical amount of air required to oxidize the mercaptans is used, the mer- `captan sulfur content of the distillate, being charged to the tank within reasonable limits, has no effect on the time required for sweetening but if less than the theoretical amount of air is used then the time required for sweetening increases with the mercaptan sulfur content. Furthermore, we find that as long as the tank bottoms are sweet and more than 100% air is used, the copper naphthenate dosage, within reasonable limits, has no effect on the time required to sweeten but here again, even with sweet bottoms in the tank but with less than the theoretical amount of air, an increase in the quantity Average Phenylene- Vol. Copper l Percent Run Residence diamine, Percent Type Caustic Naphthe- Air Rate, Theoretical RSH-S e, lbs./M Caustic nate, lbs/M lha/Hr. Air of Charge Hours bbls. bbls.

2. 5 9. 2 0. 022 alcoholic. 9. 6 13. 2 139 0. 034

19 11. 2 0.091 aqueous.. 6. 2 15.0 124 0. 053 18 9. 6 0.019 alcoholic. 5.6 no air 0. 064

In these runs the orifice was used except in run E. Run G shows the effect of using an expendable amount of aqueous caustic; at the end of 19 hours the naphtha was still not sweet. Run H shows the effect of not introducing air; in this case at the end of 18 hours the naphtha had not become sweet. N,Ndisalicylal1,2-diaminopropane was added to the sweetened naphtha in proportions of approximately three parts to four parts of the copper naphthenate. The sweetened naphtha products had satisfactory copper dish and ASTM gum tests and the induction period by the ASTM oxidation stability test was satisfactory. The gravity, Reid vapor pressure, and distillation were not altered significantly. An air injection of even up to 0.035 pound of air per barrel of naphtha did not cause the loss of light ends.

of naphthenate decreases the time required for sweetening. We also iind that when the tank bottoms are sweet the alcoholic caustic dosage, within reasonable limits, does y not affect the sweetening time as long as the theoretical cases tend to cause the vseparation of an aqueous-alcoholic phase which may be more or less'emulsied with some sweet naphtha in the bottom. It is felt that such alcoholic sodium naphthenate will act as a peptizer or dispersing agent for the fresh incoming naphtha-copper naphthenatealcoholic caustic system and that such a homogeneous system will react faster than a heterogeneous'system and also will aiord greater solubility of the air or oxygen to speed up the reaction.

Y In order to improve the contacting of the incoming charge oil with the sweetened naphtha in the bottom of the settling tank, naphtha from the lower part of tank 11 is recirculated to an upper portion of the tank or to the incoming line 10. For these purposes a pump 20 is provided which draws bottoms from the tank 11 and directs them either through line 21 to an upper portion of the tank or through a line Z2 to the line 10 preferably up stream from the orifice 13. The circulating sweetened naphtha will contain a concentration of caustic and other constituents that promote the sweetening reaction and by contacting the oil being sweetened with these components the rate of sweetening is increased.

Instead of employing the particular alcohols mentioned hereinbefore for the alcoholic metal hydroxide solutions, acetylem'c alcohols, olefnic lalcohols and glycols may be used, such for example as methylbutyonl, dimethyloctynediol, allylalcohol and ethylene glycol. The acetylenic and olefinic alcohols provide the unsaturation which is conducive to the sweetening reactions and consequently are well adapted for use in-the treatment of straight run stocks.

Our investigations have shown that when admitting the oil into a lower portion of the settling or run-down tank in the normal manner the oil at the top of the tank will ordinarily have the highest-mercaptan sulfur content while the oil at the bottom of the tank will have the lowest content. This elect is believed to be due to the presence of greater portions of the sweetening reagents in the lower sections of the tank. VConsequently an advantageous method of operation is to introduce the mixture of o il and additives at the top of the tank or at the surface of the oil by means of a floating lswing line. By this procedure the suspended caustic is required to pass through the total depth of the oil and While the tankV is being filled there will be suspended caustic at all levels. Additionally bottoms from tank vmay be withdrawn and circulated through line 21 to an upper portion of the tank or through line 22 to the incoming stream of oil and additives owing in line 10.

It has been found that the addition of cobalt naphthenatev to copper naphthenate in the sweetening reaction produces surprising results. The addition of even small quantities of cobalt naphthenate to the copper naphthenate produces a synergistic effect in increasing the rate of sweetening. This synergistic effect is particularly noticeable in the treatment of stocks which either have high contents of mercaptan sulfur or contain mercaptan sulfur compounds of particular refractoriness `and which in either case are diicult to sweeten. In a series of runs a naphtha stock containing 0.085 gram per liter of mencaptan sulfur was treated. In each case the naphtha was contacted with N,Ndi-sec.-butyl-para-phenylenediamine in a quantity of 10 pounds per 1000 barrels of naphtha, with alcoholic caustic amounting to 0.02 volume percent of the naphtha and with either copper naphthenate `or cobalt naphthenate or with certain mixtures of copper naphthenate and cobalt naphthenate in each case using 5 lbs. of the naphthenate per 1000 barrels of naphtha. The treatments were made in the presence of air. 'I'he following table shows results obtained by treating with these additives, giving the mercaptan sulfur content in grams per liter initially, that is, immediately after the contacting and after various periods of standing. In run l copper naphthenate itself was used. In run 2 cobalt naphthenate itself was used. In run 3 a mixture of 90% copper 6 naphthenate and 10% cobalt naphthenate was used and in run 4 50% copper naphthenate and 50% cobalt naphthenate.

Runl Run2 Run3 Run4 Ratio Copper Naphthenate to cobalt Naphthenate BSH-S, g./l.:

Initial After 12 hrs After 24 hrs-- After 60 hrs.

The use of mixtures of copper naphthenate and cobalt naphthenate in combination with the other additives thus presents an advantageous method of sweetening particularly as regards stocks that are diiiicult to sweeten.

Both straight run naphtha and thermally cracked naphtha generally sweeten more slowly by additive or inhibitor sweetening than light catalyst cracked naphtha. A particular advantage of the invention is concerned with the additive sweetening of blends of straight run and thermally cracked naphtha. Thus the process of the invention involving the contacting with the phenylenediamine and with expendable amounts of alcoholic caustic and copper naphthenate has been applied in the additive sweetening of Various blends of straight run and thermallycracked naphtha. It was found that the addition of straight run naphtha to thermally cracked naphtha makes it possible to quickly sweeten the straight run naphtha. As much as 40-50% of the cracked component may be added to the straight run naphtha to obtain rapid sweetening and to produce a product of satisfactory gum test.

Obviously, many modifications and variations of the invention, as hereinbefore set forth, may be made Without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicatedin the appended claims.

We claim: Y

l. In the additive sweetening of light hydrocarbon oils containing mercaptans the process that comprises rst contacting the oil, in the presence of air in an amount at least approximately as great as the theoretical amount required to oxidize the mercaptans contained in the oil, with a phenylenediamine oxidation inhibitor and an alcoholic alkali metal hydroxide solution in minute and expendable quantity, and subsequently contacting said oil with a metal naphthenate selected from the group consisting of copper naphthenate and cobalt naphthenate in minute and expendable amount and permitting the oil to become sweet in the presence of the additives.

2. In the additive sweetening of light hydrocarbon oils containing mercaptans wherein the oil is passed in a stream through a pipe to an enlarged settling zone the process that comprises introducing into a first portion of the stream of oil a phenylenediamine oxidation inhibitor, an alcoholic alkali metal hydroxide solution in minute and expendable quantity and air in an amount at least approximately as great as the theoretical amount required to oxidize the mercaptans contained in the oil, introducing into a subsequent portion of the stream of oil a metal naphthenate selected from the group consisting of copper naphthenate and cobalt naphthenate in minute and expendable amount and permitting the oil to become sweet in the settling zone.

3. In the additive sweetening of light hydrocarbon oils containing mercaptans wherein the oil is passed in a stream through a pipe to an enlarged settling zone in the process that comprises introducing into a first portion of the stream of oil a phenylenediamine oxidation inhibitor, an alcoholic alkali metal hydroxide solution in minute and expendable quantity and air in an amount at least approximately as great as the theoretical amount required` to oxidize the mercaptans contained in` the oil,

7 introducing into a subsequent portion of the stream of oil a metal naphthenate selected from the group consisting of copper naphthenate and cobalt naphthenate in minute and expendable amount, permitting the oil to become sweet in the settling zone, and thereafter adding a metal deactivator to the oil.

4. In the additive sweetening of light hydrocarbon oils containing mercaptans wherein the oil is passed in a stream through a -pipe to an enlarged settling zone the process that comprises introducing into a rst portion of the stream of oil a phenylenediamine oxidation inhibitor in a quantity of about to 10 pounds per 1000 barrels of oil, an alcoholic alkali metal hydroxide solution in a quantity of about 0.002-G.05% by volume `of the oil and air in an amount at least approximately as great as the theoretical amount required to oxidize the mercaptans contained in the oil, introducing into a subsequent portion of the stream a metal naphthenate selected from the group consisting of copper naphthenate and cobalt naphthenate in a quantity of about l to pounds per 1000 barrels of oil and permitting the oil to become sweet in the settling zone.

5. In the additive sweetening of light hydrocarbon oils containing mercaptans wherein the oil is passed in a stream through a pipe to an enlarged settling zone the process that comprises introducing into a first portion of the stream of oil a phenylenediamine oxidation inhibitor in a quantity of about 5 to 10 pounds per 1000 barrels of oil, an alcoholic alkali solution of sodium hydroxide in a quantity amounting to about 1-30 pounds NaOH per 1000 barrels of oil and air in an amount at least approximately as great as the theoretical amount required to oxidize the mercaptans contained in the oil, introducing into a subsequent portion of the stream a metal naphthenate selected from the group consisting of copper naphthenate and cobalt naphthenate in a quantity of about 1-10 pounds per 1000 barrels of oil and permitting the oil to become sweet in the settling zone.

6. In the additive sweetening of light hydrocarbon oils containing mercaptans wherein the oil is passed in a stream through a pipe to an enlarged settling zone the process that comprises introducing into a first portion of the stream of oil N,N'-di-sec.-butyl-para-phenylenediamine, an alcoholic alkali metal hydroxide solution in a quantity of about 0.002-0.05% by volume of the oil and air in an amount at least approximately as great as the theoretical amount required to oxidize the mercaptans contained in the oil, introducing into a subsequent portion of the stream of oil copper naphthenate in an amount of about 1-10 pounds per 1000 barrels of oil and permitting the oil to become sweet in the settling zone.

7. In the additive sweetening of light hydrocarbon oils containing mercaptans wherein the oil is passed in a stream through a pipe to an enlarged settling zone the process that comprises introducing into a first portion of the stream of oil N,N-di-sec.-butyl-parapheny1 enediamine, an alcoholic solution of sodium hydroxide in a quantity amounting to about l-30 pounds NaOH per 1000 barrels of oil and air in an amount in excess of the theoretical amount required to oxidize the mercaptans contained in the oil, introducing into a subsequent portion of the stream of oil copper naphthenate in an amount of about l-10 pounds per 1000 barrels of oil, permitting the oil to become sweet in the settling zone and thereafter adding salicylalaminoalkane to the oil.

8. The process as deiined in claim 7 wherein the salicylalaminoalkane added to the oil is N,N-disalicylall,2 diaminopropane.

9, In the additive sweetening of light hydrocarbon oils containing mercaptans the process that comprises contacting the oil in the presence of air with a phenylenediamine oxidation inhibitor, an alcoholic alkali metal hydroxide solution in minute and expendable quantity and metal naphthenate in minute and expendable amount and consisting essentially of copper naphthenate and cobalt 8 naphthenate and permitting the oil to become sweet in the presence of the additives.

' 150."The process as defined in claim 9 wherein the cobalt naphthenate constitutes atleast about 10% of said metal naphthenate.

11. In the additive sweetening of light hydrocarbon oils containing mercaptans wherein the oil is passed in a stream through a pipe to a settling tank, the process p that comprises introducing into the stream of oii a phenylenediamine oxidation inhibitor, an alcoholic alkali metal hydroxide solution in minute and expendable quantity, a metal naphthenate selected from the group consisting of copper naphthenate and cobalt naphthenate in minute and expendable amount and air in an amount at least approximately as great as the theoretical amount required to oxidize the mercaptans contained in the oil and contacting the oil being sweetenedA with previously sweetened oil containing constituents which promote the sweetening reaction.

12. In the additive sweetening of light hydrocarbon oils containing mercaptans wherein the oil is passed in a stream through a pipe to a settling tank, the process that comprises introducing into the stream of oil a phenylenediamine oxidation inhibitor, an alcoholic alkali metal hydroxide solution in minute and expendable quantity, a metal naphthenate selected from the group consisting of copper naphthenate and cobalt naphthenate in minute and expendable amount and air in an amount at least approximately as great as the theoretical amount required to oxidize the mercaptans contained in the oil, withdrawing sweetened oil from the bottom of the tank containing constituents which promote the sweetening reaction and circulating the withdrawn oil to an upper portion of the tank.

13. In the additive sweetening of light hydrocarbon oils containing mercaptans wherein the oil is passed in a stream through a pipe to a settling tank, Ithe process that comprises introducing into Vthe stream of oil a phenylenediamine oxidation inhibitor, an alcoholic alkali metal hydroxide solution in minute and expendable quantity, a metal naphthenate selected from the group consisting of copper naphthenate and cobalt naphthenate in minute and expendable amount and air in an amount at least approximately as great as the theoretical amount required to oxidize the mercaptans contained in the oil, withdrawing sweetened oil from the bottom of the tank containing constituents which promote the sweetening reaction and injecting the withdrawn oil to the stream of oil and additives owing to the tank.

14. In the additive sweetening of light hydrocarbon oils containing mercaptans wherein the oil is passed in a stream through a pipe to ay settling tank, the process that comprises introducing into the stream of oil a phenylenediamine oxidation inhibitor, an alcoholic alkali metal hydroxide solution in minute and expendable quantity, a metal naphthenate selected from the group consisting of copper naphthenate and cobalt naphthenate in minute and expendable amount and `air in an amount at least approximately as great as the theoretical amount required to oxidize the mercaptans contained in the oil, permitting the oil to become sweet in the settling tank, withdrawing from the bottom of the -tank settled alkaline components comprising alkalli metal hydroxide, phenolate and naphthenate and recycling such settled components into Contact with the oil being sweetened.

15. In the additive sweetening of a light hydrocarbon oil containing mercaptans wherein the oil is passed in a stream through a pipe to an enlarged settling zone, the process that comprises introducing into a first portion of the stream of oil a phenylene-diamine oxidation inhibitor, an alcoholic alkali metal hydroxide solution and air in an amount at least approximately as great as the theoretical amount required to oxidize the mercaptans contained in the oil, and introducing into a subsequent portion of the stream of oil, copper naphthenate and cobalt naphthenate.

16. In the additive sweetening of a light hydrocarbon oil containing mercaptans wherein'the oil is passed in a stream through a pipe to a settling tank, the process that comprises introducing into the stream of oila phenylene-diamine oxidation inhibitor, an alcoholic alkali'- as great as the ytheoretical amount required to oxidizethe mercaptans contained in the oil, withdrawing `sweetned oil from the bottom of the tank containing constituents which promote the sweetening reaction and cir- Rosenwald Nov. 4, 1952 Krause et a1. Dec. 22, 1953

Claims (1)

1. IN THE ADDITIVE SWEETENING OF LIGHT HYDROCARBON OILS CONTAINING MERCAPTANS THE PROCESS THAT COMPRISES FIRST CONTACTING THE OIL, IN THE PRESENCE OF AIR IN AN AMOUNT AT LEAST APPROXIMATELY AS GREAT AS THE THEORETICAL AMOUNT REQUIRED TO OXIDIZE THE MERCAPTANS CONTAINED IN THE OIL, WITH A PHENYLENEDIAMINE OXIDATION INHIBITOR AND AN ALCOHOLIC ALKALI METAL HYDROXIDE SOLUTION IN MINUTE AND EXPENDABLE QUANTITY, AND SUBSEQUENTLY CONTACTING SAID OIL WITH A METAL NAPHTHENATE SELECTED FROM THE GROUP CONSISTING OF COPPER NAPHTHENATE AND COBALT NAPHTHENATE IN MINUTE AND EXPENDABLE AMOUNT AND PERMITTING THE OIL TO BECOME SWEET IN THE PRESENCE OF THE ADDITIVES.

Images